Hi thenerdicpianist06!
You’ve definitely played a good amount of 8-12 minute large scale works. I’d have to agree with symphonicdance that you should go for a longer large scale work:
Here are a few good ones to look at
Schumann sonatas 1-3: I am partial to the 2nd sonata and it is probably the one closet to your level. Difficult, but totally manageable.
Chopin sonatas 2-3: very magnificent and difficult works but would definitely be worth a shot. They are both around 26 minutes, so very long.
Schubert sonatas (romantic-ish):the later ones are larger, the big Bb is my favorite. The C minor is also very good.
Brahms-Handel variations: extremely tricky but one of my favorite pieces of all time. The fugue is absolutely wild.
Liszt Dante sonata
Liszt Sonata B minor or Rachmaninov sonata No. 2: if you could handle them lmao. Incredibly difficult and mature.
There are a lot more of these works out there but these are just a few suggestions. You can also check out Medtner and Alkan and other works by Brahms, Schumann, Chopin and Liszt.
Note: the most important thing about picking a large scale work is to make sure you love the work and not base it on other people’s opinions or base it on difficulty. Just a little bit of advice