So I attempted to make my first Real homebrew Subclass, and... I definitely feel like it's somewhat overpowered. I love it thematically and mechanically, but I don't know how to balance it.  If any of you guys could help me out with this, I'd love to see this subclass come into fruition!

Warrior of the Roots

Connect yourself with the Earth.

Warriors of the Roots share an intimate connection with nature, and the earth as a whole. They allow a physical connection between themselves and the ground, becoming one with nature. As opposed to other Monks, who dart around in acrobatic antics, Warriors of the Roots stand stalwart, pulling foes to them.

Level 3: Rooted Stance

You learn how to stand firm, rooting yourself to the ground, carrying the towering might of a tree. To do this, spend an  action on the start of the turn. For as long as you stay in your rooted stance, you gain the following benefits:

• Still While rooted, any movement speeds you have are set to zero, and you also automatically fail any acrobatics checks. Enemies also have advantage against you.
• Nature Connection Gain advantage on all Nature checks while rooted, as the connection to the earth gives you knowledge of it.
• Bonus AC As roots cover areas of your body, they create a natural armor, giving you an AC bonus equal to half your Wisdom modifier, rounded up (minimum of +1).
• Prone/Forced Movement Immunity While Rooted, you gain immunity on any rolls to stop you from falling prone, or being forced to move in any way.

To leave Rooted stance, you must spend an action to leave it. All the effects of the stance end as soon as you do.

An enemy can force you out of Rooted Stance with a successful hit, attempting to break your connection. It follows the rules of concentration, needing you to make a Constitution Save to not end this stance. You can also spend 2 Focus Points to pass the check instead. The number of required Focus Points raises by 1 for each time this happens.

Level 3: Rhizome Wrath

While Rooted, you can shoot forth Grasping vines toward enemies, pulling them towards you, while you don’t have to move a foot. As A bonus action or Reaction, you may choose an enemy within 20 Feet. They make a strength saving throw of 8 + Proficiency bonus + Wisdom Modifier. If they fail, they are pulled up to 20 feet toward you.

You are allowed to spend at least one Focus  point to leave the enemy restrained when they are pulled to you. They must make a strength saving throw of 8 + Wisdom + Number of Focus Points used each turn, to escape from the grapple.

Level 6: Rooted Overgrowth

Whilst rooted, the ground in a 15 foot circle around you becomes covered in your roots. That area becomes difficult terrain for enemies. You can forgo the effects of the Difficult terrain for your allies. Your roots terrain overrides any other terrain it may overlap with. Also, when someone falls prone within the area, you can move them around, pulling them to you as a reaction immediately, and if you pull them into range, you can make an unarmed strike against them as part of that reaction.

Level 11: Flawless Foundation

While you are in Rooted stance, you can choose to spend 2 Focus Points to Strengthen your connection with the earth. As more roots cover you, gain the following benefits:

• Reinforced Body While in this stance, you can spend Focus points to aid yourself. For each Focus Point spent, add 10 temporary HP. All of this Temporary HP disappears as soon as you un-root yourself. Also, while Flawless foundation is active, gain a bonus to Constitution Saving throws equal to half of your Martial Arts die, rounded down.
• Improved Resistance Gain a resistance to Bludeoning, Slashing, and Piercing Damage done to you with Nonmagical weapons.
• Improved Wrath Double the Range of Rhizome Wrath, and allow it to target a number of creatures equal to your Wisdom Modifier. Also, add +2 to the DC for any strength saving throws you make to pull or restrain enemies using this spell.
• Leeching Roots Once per turn, when hitting an enemy with an unarmed strike, deal an extra roll of your Martial Arts Die of your damage type. Also, gain Temporary HP equal to the Number Rolled.
• Sense of Earth Gain Tremor Sense within a range of 60 Feet.

After activating Flawless Foundation, it continues for as long as you stay in Rooted stance. However, to leave this Form, instead of only taking an action, you spend your action, Bonus action, and Reaction.

Level 17: Terrible Terraformer

Your Rooted Overgrowth ability grows stronger. It gains the following Benefits:

• Reaching Radicles The Range of your Overgrowth increases to 30 Feet.
• Dreadful Dificulty In the Overgrowth, the Roots actively try to hinder your foes. One foot of Movement they take costs 4 Feet of their movement. Also, if they fall Prone in the Area, they are automatically pulled 5 feet towards you, and must make a Strength save of 8 + Proficiency + Constitution, or be restrained, and pulled 5 feet toward you.
• Subterranian Support Instead of the Negative Effects of the Overgrowth, Allies in the Area receive Advantage on any roll to avoid forced movement, or being knocked prone. Also, the monk can choose to Give the Effects of Steps of The Wind to an Ally within the Area. You still must spend the required Focus Points to do so.
• Hunger of Gaia When an enemy dies within your Overgrowth, either:
  1. Gain 2 Focus Points.

OR

1. Gain 20 Temporary HP. This Temporary HP stacks with other effects of this subclass. Much like the other effects, this Temporary HP disappears once you leave rooted stance.
   
   Thats everything! I also still want to keep it consistent, and maybe lean into turning the character very weak once they up-root themselves, or get up-rooted.

Very interesting concept, but it does need work balancing, some features are net negatives, others are clunky. I'll do my best here to provide specific suggestions. I'm going to break it up into spoilers to avoid an overwhelmingly long post.

Level 3: Rooted Stance

Comments: Requiring an action is a high cost for something that provides only marginal defensive benefits, the AC calculation is also odd and confusing considering Monk's already add their Wisdom to their AC. The enemy Advantage is also a very high cost to pay for this. While I understand the logic of this feature, it ends up being a net negative for the player character.

Suggestion: Level 3: Put Down Roots

 Level 3: Rhizome Wrath

I get what you are going for here, but a Reaction needs to be in response to something, and using a whole bonus action to have a 50% (or less) chance to move one enemy into reach so you can hit them, is not a good option when you could instead move to the enemy for free and be guaranteed to be able to attack them 1-3 times (hence why I added the 20 ft reach to the Rooted stance so you're at least able to guarantee you can attack enemies within 20 ft of you). It's also really bad to have all your subclass features tied to one specific stance because there will be times when it's not possible / practical to be in that stance and in those cases the character might as well not have a subclass at all. Especially since the Rooted stance is such a debuff to the character most of the time I wouldn't want to use it so the entire subclass is basically useless.

Suggestion: Level 3: Rhizome Web

 Level 6: Rooted Overgrowth

This is the first good feature in this subclass, but 15 feet of difficult terrain isn't that great especially since this Monk wants enemies to get close to it because it can't get close to them. Typically you see these difficult terrain features on casters because those classes don't want enemies to get close and hit them. Giving this subclass reach does mitigate this problem a fair bit, so I think with my adjustments above this feature works. Just some wording improvements:

 Level 11: Flawless Foundation

There's just too much going on with this feature. Many of which aren't very good, 10 temporary hit points is not a good trade for a Focus Point. Bonuses to saving throws are kind of redundant around this time because they are soon to get proficiency with all saving throws. Bludge/Slash/Pierc damage resistance is super powerful and is typically a whole class feature just in and of itself. Improved wrath doesn't make sense the way it is written. And I feel like you need something that doesn't depend on being in the Rooted stance.

I like the tremorsense that feels very thematic, but I'd be tempted to make is permanent / always on. 

Suggestion: Level 11: Sturdy as Soil

 Suggestion: Level 11: Sense Vibration

 Level 17: Terrible Terraformer

This one is absolutely broken, at these levels most enemies will have an option other than walking (teleport, flying, burrowing etc..) so the extra difficult terrain probably isn't going to do anything most of the time, and when it does it will cause enemies to completely avoid you which is not what you want as a monk. Forced movement advantage is fine but nothing particularly exciting, similarly regaining Focus Points is not necessary at these levels. 17 Focus Points is more than enough to use every feature you have that costs Focus every round in a combat and still not run out. It's also a major no-no to allow temporary hit points to stack - temporary hit points not stacking is a fundamental rule of 5e. Good ideas but based on my experience this will not live up to what is on the paper in actual play.

Suggestion: Level 17: Reaching Tendrils