Being in a similar position, I'm considering iCloud+ Mail myself. It's cheap, comes with custom domain support and if you're already in the Apple ecosystem, cou

Being in a similar position, I'm considering iCloud+ Mail myself. It's cheap, comes with custom domain support and if you're already in the Apple ecosystem, could integrate nicely. Their web UI looks quite.. simple and likely lacking in features, it might still be just fine to use it with an IMAP client.