The easiest and best filter is to screen emails. Only emails that were screened in once go to your inbox. It's that easy. HEY.com introduced it, and I can't see email without it; that's why I integrated it into my TUI email client, neomd [1]. Since then, when I get an email from Amazon that lands in my "To Screen" box, I am automatically alerted and know it is potentially spam, because I have approved Amazon and legit emails land in my inbox. Check it out, it's that easy. Neomd works with Fastmail or any other IMAP/SMTP email provider.
No AI needed, and also no stupid AI summary, as you only get a few legit emails to your inbox, never spam anymore.
This is basically where I (and I imagine many others) have landed with the telephone. Anyone not in my contacts goes to voice mail. Made my phone usable again.
So the natural extension of this would be plugins which have curated open source allow-lists? Similar to how I trust uBlock Origin's default ad filtering block-lists, I would similarly trust a curated open source allow-list for email domains, and then I would add my own from the "to screen" folder?