Aside from using Gmail, which has quite good spam filtering, my solution to email spam is siloing: using a separate email account for different categories of account sign-ups, etc. I just checked my 'good' email's spam folder, and there's nothing there - I get maybe one spam email every few months. (In order to reduce friction, I have autoforwarding from other emails, which doesn't resend spam with gmail - but there are other solutions which would presumably work for any email provider).

The only downside is, with paid email accounts, this could be monetarily problematic - which I don't really see a solution for, unfortunately. But, it's definitely way easier to filter email spam than physical/phone spam.