I do this too, though sometimes it leads to confusion.
FWIW, Firefox's Relay integrates into Bitwarden so you can generate emails on the fly when creating new accounts. Downside and upside is that I never know what my email address or password is.
The huge benefit is I can write down an email that'll work because I own @somedomain.mozmail.com and it'll always redirect. I do the same thing with cloudflare because I also own myrealname.com
But honestly I hate all this because the real problem is that email is a bottleneck and it is stickier than phone numbers. But my email is floating around on a bunch of lists because I've had it for years. Frankly, gmail is pretty bad about removing spam. There's a lot of spam I catch using simple filters from Thunderbird.
The extra benefit is that I'm planning on moving away from gmail and all these relays make it easier to redirect everything to a new location. So I still recommend it. You can shutdown addresses that are being abused or shared more easily but that's hard to do with your long term email address.