Typing with LaTeX within Vim can be as fast (or even faster) than in the Word processors. You can use the power of Vim plugins, concealments, and customized snippets. Most probably the same can be done inside Emacs as well. See the excellent article[1] on how to set up your Vim to follow the mathematics lectures in real time.

[1] https://castel.dev/post/lecture-notes-1/