The Insurgent, a fighter that never fights fair

I just finished making a new fighter subclass and I wan to figure out if it’s balanced or not. It’s a subclass based around screwing with terrain and using items such as oil, caltrops and nets to screw with the enemy.

Fight dirty and turn tail

Insurgents are unpredictable combatants that use everything in their arsenal against stronger or vast forces. They can be plucky rebels, savvy improvisers or brutal extremists. Regardless, they will blind, sweep and strangle their foes in order to secure victory.

Level 3: Dirty Tactics

Your tenacity and quick thinking has allowed you to alter the terrain and disrupt enemies to your advantage. 

Ruthless Points. You can use a Ruthless point to do one of the abilities below. You have Ruthless points equal to your PB. You regain all Ruthless Points after a short or long rest.

Saving Throws. If a Dirty Tactic requires a saving throw, the DC equals 8 plus your Strength or Dexterity modifier (your choice) and Proficiency Bonus.

Kick Up Dust. You replace one attack; You create a 10-foot-radius Sphere of fog centered on a point within 5 feet. The Sphere is Heavily Obscured. It lasts until the end of your next turn or until strong wind (such as one created by Gust of Wind) disperses it.

Splay Mud. You replace one attack; choose a point within 10 feet of you, a 10-foot square acts as Difficult Terrain.

Heavy Underhand. If an enemy fails a save from you on your turn, they become prone or are pushed 5 feet away from you.

Move Through Ranks (7th level). As a Bonus action, you ignore difficult terrain and can move through enemy spaces until the end of your turn.

Disorienting Strike (7th level). When you hit with a weapon, the target has disadvantage on its next save.

Quick Hideout (10th level). As a bonus action, you can make a 10 foot square within 5 feet become eligible to hide in.

Level 3: Improved Improvisation

Anytime an item that you used an action on forces a saving throw, you may choose for the DC to equal your Dirty Tactic saving throw.

Level 7: Resourcefulness

Proficiency. You gain proficiency in an Artisan’s tool of your choice and in Survival.

Preparations. When you finish a long rest, you may choose to create Ball Bearings, Caltrops, Oil, Rope, Hunting Trap or a net. The item lasts until you finish another Long Rest, at which point the item falls apart.

Level 10: Item Modifications

You have modified your items to hold properties of different ones in order to become more effective:

Barbed. If a target fails a saving throw against you, they take Piercing damage equal to half your PB for each attack it makes until the start of your next turn.

Flammable. If the target fails a saving throw against you, they take an additional 2d6 fire damage the next time it takes fire damage.

Harrowing. Once a round when you hit with an attack or the target fails a save from you, the target makes an additional concentration check with a DC of 10.

Level 15: Unavoidable

Once per long rest, whenever an enemy is Grappled, Prone or Restrained by you, they become Incapacitated until the end your next turn.

Level 18: Rebel’s Escape
Once per short rest, you can use three Ruthless points to cast Freedom of Movement without material components.