inspired by @elan we started brainstorming ideas to suggest accessibility capitalization when typing hashtags. kind of a tricky problem, and here is my first take on it, using the aho corasick algorithm as implemented by https://github.com/BobuSumisu/aho-corasick.
My hack code is here:
https://github.com/wesen/majuscule
You can try it out for the evening (running on a single core on my laptop, hopefully it won't crash): https://6f0d-108-7-201-60.ngrok.io
Get in touch if you want to help!