Are these changes to the Thunder Step spell balanced as a homebrew spell?

Question

My DM is letting a few of us create custom spells for our campaign, and I thought I would run my current idea by some people. The main thing I'm curious about is if the level is balanced with the effect and if my changes to its base (the Thunder Step spell) are balanced with other spells of its level.

Meteor Crash

3rd-level conjuration

Casting Time: 1 action

Range: 90 feet

Components: V

Duration: Instantaneous

You teleport yourself to an unoccupied space you can see within range. Upon arrival the air ignites around you, forcing each creature within 10 feet of you except yourself to make a Dexterity saving throw, taking 3d12 fire damage on a failed save, or half as much damage on a successful one. Flammable objects in the same area ignite if they aren't being worn or carried.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d12 for each slot level above 3rd.

As stated earlier, this is based off of the Thunder Step spell. I figure changing the "thunder can be heard from up to 300 feet away" as a side effect to igniting objects is an equal change, but I hoped to trade off being able to take someone with me when I teleport to an increase in damage dice. I don't know if changing the damage happening at the endpoint of the teleport affects the level it would be.

Answer 1

This should be balanced

Though there aren't exactly other spells to compare to, we can look at what you've done.

You've removed the ability to carry extra objects and also move a creature with yourself, this removed a rather strong utility option for the spell, and to compensate for this you've only changed the average damage by +3 (actually less because of the chance of success on the saving throw) and that's not all; you've also changed the damage type to one of the most resisted and immuned damage types in the game. This further lowers the severity of this alright slight modification.

Overall, your changes to the damage alone probably come close to balancing out the spell, and then you've also removed some utility making the change almost assuredly equivalent (if anything I feel your change may be weaker than the original, though upcasting is also improved so at higher levels they would switch in terms of power)