There is also Firefox relay which gives you 5 email aliases. I have found that some services such as discord do not accept addy or simplelogin domains but they accept firefox relay domain which is mozmail.com if I am not mistaken
Problem is that this domain (whether it includes your real name or not) is still related to your person as you are the sole user.
If you created accounts at Google, Amazon and Facebook using a schema of servicename@thisspam.com, don't you think they'd be able to tell it's the same person who created those accounts?
With the likes of google.quothfaaoa@aliassingservice.com, amazon.qwrlaklfas9@aliassingservice.com and facebook.1afglasdah@aliassingservice.com, that identification vector is simply ruled out.
This is going to be controversial, but if I was a user of these three scummy sites what you say above isn't the hill I'm willing to die on or care about.
However I have half a dozen domains, I could quite easily add one or two more for dumb shit like this if I wanted to.
A point can be made here for email providers that also provide aliasing services such as Protonmail/SimpleLogin: Since they're the same entity, using an aliasing service requires no additional trust.