Do you prefer not to use a catchall alias[1] to prevent someone from just sending mail to garbage12345@yourdomain or for some other reason? I also use unique addresses for every website account I have but with the catchall, I don’t need to spend the 20 seconds to create the alias. It’s just automatically there. I can’t think of any issues I’ve had by using the wildcard alias.
[1]: https://www.fastmail.help/hc/en-us/articles/1500000277942-Ca...