Both are fine choices depending on your requirements. The thing with external alias services, you are not in control of the addresses/domain. Catch-all addresses are essentially aliases you manage, but something like Simplelogin does have the benefit of hiding your domain name.

Spam is not a big deal on catch-all. A couple of times a year I do get a spam mail to some arbirtary address, but that’s more or less it.

Let us know when you want some help with the server costs!