Flame of the Guðir Haust

Ok guys this is the rough draft for a new subclass I am making for Fighters in my WIP setting for an upcoming campaign. Feedback on how I can improve/better balance this class is not only appreciated but also respectfully requested.

Searing Flame

Your training has lead you to begin communing with the Fire Elementals within the mountains. Through this communion you have learned to harness some of their power.

As a bonus action you may focus the heat from your allies into your weapon, for the next minute your weapon attacks deal 1d6 fire damage in addition to their regular damage and type. When you reach 10th level this increases to 2d6.

Kiss of Flame

Your communion with the Elementals has taught you to withstand heat, and their blessing has allowed you to often shrug off even the great balls of arcane fire wielded by the arcanists of Gu'Denviir.

When you choose the archetype you gain resistance to fire damage.

Lure of Flame

Your connection with fire elementals has strengthened further, allowing you to increase your presence on the battlefield through flames. Beginning at 7th level you may use a bonus action to teleport to a flame within 30 feet of you. This flame must be large enough for you to stand in. When moving through flames in this way you do not take damage from the fire unless you are still standing in it at the start of your next turn. You may do this a number of times per day equal to your proficiency bonus.

Wreathed in Flame

With the strength of your bond with fire elementals growing, they have helped hone the potency of your Searing Flame. Beginning at 10th level, when you hit a creature while Searing Flame is active you may attempt to have the target erupt in flames. The target must succeed on a Dexterity saving throw, DC= 8 + your proficiency bonus + your Constitution modifier. On a failed save the target takes 3d6 fire damage as it becomes wreathed in flames. The target will take 2d6 damage at the start of each of its turns for 1 minute, or until it or another creature uses and action to douse the flames. On a successful save the target takes half the damage and suffers no further effect.

You may use this feature a number of times equal to your proficiency bonus.

Cordon of Flame

Your affinity with flame has grown to the point that you can use flame to cordon off sections of the battlefield. Thus allowing you to split the enemies forces. Beginning at 15th level you may cast wall of fire, once you use this feature you may not do so again until you take a short or long rest. The DC is calculated with this formula: 8 + your proficiency bonus + your Constitution modifier.

Avatar of Flame

You have learned to become one with the elementals you call friends. Beginning at 15th level you may use your action to transform into an avatar of flame for 1 minute gaining the following benefits:

Your movement speed increases be 20 feet.

You are immune to fire and poison damage.

You can move through a space as narrow as 1 inch wide without squeezing. A creature that touches you or hits you with a melee attack while within 5 feet of you takes 2d10 fire damage. In addition, you can enter a hostile creature's space and stop there. The first time you enters a creature's space on a turn, that creature takes 2d10 fire damage and catches fire; until someone takes an action to douse the fire, the creature takes 2d10 fire damage at the start of each of its turns.

You shed bright light in a 30-foot radius and dim light in an additional 30 feet.

Once you use this ability you may not do so again until you finish a long rest.

You may add your Constitution modifier to damage from your Searing Flame ability.