Let's try here in Mastodon if LaTeX with Emacs users can help to solve any of these questions. (thanks in advance!)
https://emacs.stackexchange.com/questions/85603/how-to-set-latexmk-options-using-it-with-auctex
https://emacs.stackexchange.com/questions/85602/how-to-set-latexmk-options-using-it-with-polymode