A simple, open-source spam filtering approach gets rid of 99.99% of spam. My total filtered email volume in a day is in the single to low double digits in the personal account and double digits at work. This is very much in range for LLM filtering of mail that passes the mechanical spam filter.

I have an appscript that uses Gemini for this. Works great. Usage is in in the free tier. I even had Gemini write the appscript.