i'm of the sentiment that what will help 'advanced' performers continue to improve is a move to really hone and refine the fundamentals. that is, look at what the top/best are really known for, though the flash fanfare is what gets attention, it is actually their flawless execution of the basics. that is like the old definition of virtuosity staes (not official but one i hear again and again in coaching circles), it is uncommon creativity coupled with flawless fundamentals. become an expert beginner again. really make sure you can consistently and intuitively figure out fingerings inBach (i.e your example), be able to master basic techniuqe patterns to an almost 'perfect' excecution, consistently.
on repertoire, it is not just about being able to pony up to harder (techinically) and more difficult (musically) pieces but also, to what level of refinement can you perform what are considered 'easier' works? you should be visiting pieces in the lower levels of 'difficulty' and striving to be able to learn and interpret them to a very high level , with minimal if any input/instruction.
learn to be able to cover pieces at your current level to an appropriate standard of quality but strive to be able to do that while concurrently working a larger and more diverse set of pieces in the repertoire.
learn to learn pieces faster, i.e. faster memorization, faster internalization of musical concepts and getting them performances ready in a more compressed learning time window.
focus and practice most on those things you suck the most at.
this isn't menat to be some treatise or doctrine on the subject but it is what I have in my mind for myself and as I navigate the post 'early advanced' stages of my own development.
take what you will from it. good luck and welcome to the community!