I use ProtonMail and sign up to everything with <service>@<custom-domain> so I can track what they do with my email. It's not cheap from PM, and there are load

I use ProtonMail and sign up to everything with <service>@<custom-domain> so I can track what they do with my email. It's not cheap from PM, and there are loads of hosting providers that will provide catch-all email for free with your hosting package (but with some usually pretty poor webmail client) or if you use a mail client it should work too. I like having good webmail and mail app and other things so I pay, but there are plenty of good options available. Sadly self-hosting email server is not really an option for a variety of reasons, but you should easily be able to use catch-all e-mail addresses.