I'll third this. A few years ago I set up both a website (cloudflare) and started using Firefox Relay (proxy email addresses, with a mozmail domain).

I did it to make gmail less sticky and control spam[0]. Then last year I switched to fastmail and it was so easy because I just had to point somewhere else.

Even if you keep Gmail I highly suggest people do this as it's helped with spam and gives me more control. Because I have catchall emails I can even make up an email on the spot, with pen and paper only.

[0] every website gets a unique email and a unique password. Think something like hn@foo.mozmail.com or hn@godelski.com (I don't own those domains, don't try to reach me there). Bitwarden even supports FF Relay!