You can also create aliases on most sites by adding a + and a suffix to your email

You can never disable those aliases, though. The best you can do is write a filter that sends them to trash. With a good email alias system, you can actually disable an alias, so that emails to it just bounce back.

Many services just strip out everything at the + so I instead have a catchall account use email addresses like sitename@example.com. For addresses that start getting spam, I add them to a config in rspamd that bounces them. (I self-host my email server)