I have 99th percentile typing speed on QWERTY thanks to using PCs when too young for traditional touch typing to work. My arms fly around the keyboard and I have never gotten RSI _from typing_. Using the mouse precisely for a summer where vim was forbidden (thanks big banks) did yield almost instant RSI. Trying traditional touch typing (with no movement) also agitates my arms. But imo folks should learn speedtyping techniques for qwerty to avoid RSI and skip the rabbit hole of alternate layouts and keyboards. Lot of inconvenience and more wasted time than will likely ever be saved.
The only true advancement is steno / charachorder. The actual charachorder lite isn't quite there imo (chord detection sketchy) but one of these days I will use ZMK to add the most common chords to my qwerty keychron k2 with gateron browns. Not to mention ZMK has far more features (like modtap) that you find yourself wanting once you use something like Charachorder, and Charachorder is still not open source ("someday").
If you're really in need of even faster typing than "faster than anyone you know", first reevaluate your decision-making framework, then voice dictate.