PurelyMail is a great and cheap service. It’s like $10 per year. You just set up some records (MX and TXT) on your domain provider and that’s it.
You could also self-host email, but then you need a server that’s always powered on and it adds much complexity, so I suggest to use a managed service instead.
The good thing about using your own domain is that you’re not tied to any service. You could migrate to any other provider (such as ProtonMail, FastMail, etc.) without ever changing your email address on all services.
I envy you, because my 2019 MBPro has fans always spinning and it seems slow and bugged, especially with the latest macOS.
Maybe I should just try formatting, but I don’t know if it’s worth the hassle.