how does 2) work?
do you have a catch-all service?
say I want to give my custom address to a John I've just met, can I tell them to write to john@horsellama.xyz without actually creating that address?
I use Fastmail which gives you a wildcard catchall alias, *@example.com , but you can do this even self-hosting with postfix, and I'd bet most decent email providers who let you use a custom domain also have a catchall email feature.