Sorcerer Spell Replacement Suggestions?

[biovoid]

I'm currently playing an 11th level reflavored Golden Draconic Sorcerer in a campaign that we play weekly and expect to go full 20 in. Our DM is very lenient on rulings, allowing Unearthed Arcana as long as they're the most recent edition (for example, a Minotaur would have to take the book version but a brute fighter is fine as is), and giving the party a bevy of magic items.
As it is, my sorcerer does some of the most consistently high damage in the party (which includes a Celestial Tomelock Warforged, a Half-Elf Shepherds Druid, a human Glamour Bard 8/Chainlock 3, and a Brute 3/Kensai 8), but I'm acutely aware that her current build is basically predicated on the enemies not being immune to fire damage.
Her current spell list is: Shield, Enlarge/Reduce, Scorching Ray, Shadow Blade, Counterspell, Fireball, Fly, Haste, Thunder Step, Polymorph, Wall of Light, and Investiture of Flames, as well as the standard racial spells Tieflings get. On top of that, she has the Elemental Adept feat with fire being the chosen damage type. Her cantrips that damage are Green Flame Blade, Fire Bolt, Lightning Lure and Shocking Grasp
The question arises, however, due to us having just leveled at the end of our last session; should I replace my existing spells? I haven't used Thunder Step once yet, although I know it has massive usefulness and could potentially save her. In the same vein, I rarely find myself using Enlarge/Reduce now that we're high level. Given that we play this once a week, I have couple days before I have to decide which spell I'm replacing and what I would replace it with. Should I go with some more variety in my damage output? Or would I be better off trying to grab a spell that buffs allies or myself?

[Skyblaze]

Well, if you never use it, replace it with something you may use.

I'd drop scorching ray too, one firebolt can nearly match it at level 11, quicken or twin it and its much better.

[ImproperJustice]

Do you get much use out of Shadow Blade?

Yeah, as others have said, trim the fat of any spells you don’t use or are underperforming.

Overall you have a pretty solid list. All I might recomend is:

Absorb Elements: one of the best defensive spells in the game. Requires minimal energy from you and can be a concentration saver.

Misty Step: more versatile than Thunderstep, and you can still cantrip when you use it. Recover from prone, escape from grapples, and just get into a better position.

Maybe grab an alternate damage spell like Storm Sphere, Vitriolic Sphere, or Tidal Wave.

Blink is a decent defensive spell that doesn’t require concentration.

Lastly: immolation gets panned for some prettty good reasons, but as a Sorceror you can twin it, empower it, or for hilarity subtle cast it to make some poor sod burst into flames.
Against low dex enemies it is death, or if you use it as a finisher, you destroy the enemy’s body preventing revival Shenanigans. It’s also verbal only, meaning you can use iit while grappled or restrained. As a fire sorc, you can get some extra mileage out of this one.

[Corran]

It would be very helpful to mention which 3 matamagic options you have taken.

Of the spells you have, and to repeat some of the things the other posters said:
Unless there is some synergy I am missing (any major profit from enlarging the druid or the brute/kenasi?), I would do away with enlarge/reduce, as at this level the competition for concentration spells can kill it as an option.
I would also do away with shadow blade, you are not a melee character, and if you find yourself in melee, disengaging, flying or teleporting away would be your realistic options (in contrast to staying in melee).
Scorching ray has lost a lot some of its appeal now that you cantrips have powered up once again, though I would not put much emphasis in retraining it quickly (as there are other candidates for retraining that are of less value to you).
I don't think wall of light is a good spell, I'd look to replacing it with something else (probably with wall of fire if at least one of the warlock or the bardlock have taken repelling blast as an invocation, definitely if both have RB).
Investiture of flame is meh but cool. Concentrating on it and dropping fireballs on your feet can also be fun and occasionally useful too.

I'd look to get absorb elements and misty step, possibly retraining thunder step for dimension door (or for something else, if you have any more useful spells in mind). I also like fear and dragon breath for draconic sorcerers (from a thematic point of view at least). Mage armor (cast on the druid) might also make good use of your 1st level slots, though it's difficult to justify taking it with so few spells known available (and given that you are basically retraining, it might be even harder to prioritize it). But to make ''better'' suggestions, I would have to know your matamagic options first.

[TheUser]

We need to know your metamagics to help you.

[Crgaston]

Synaptic Static will let you target an Int save for an 8d6 Psychic AOE and provide a significant debuff if they fail the save.