InEnduringGrowStrong@sh.itjust.works

That was supposed to be ‘address’ as in email address, not sure how autocorrect figured that one.

Yes and no… say if you gave the email address lemmyworldthingy@sgarcnlsdomain.com when signin up and you start receiving garbage on it, you just delete the alias and move on.
The trick is that you can have several aliases go into the same inbox so you only have to check one place, but each thing is given its own IP making it easier to identify and filter culprits.

Buying your own domain.
You can then use whatever provider, or host your email service… but at least you don’t need to change addresses when switching anymore.