@LovesTha – if you can bear the cost, a good paid service (full disclosure: I use them) is Protonmail.
If you pay for a “Visionary” account, you get custom domains; access to ProtonDrive (in beta, no desktop or mobile client yet), and full VPN access. A Visionary account is a little expensive, but worth it for the VPN and reliability. Anti Spam is ok, not the best, but pretty good. It has Mobile Clients for Mail; Calendar and VPN. The down side is there is no IMAP/POP3/SMTP access, though you can use a bridge app (they provide a Windows, Mac and Linux version) on your Machine to connect your favorite mail client.
Having no server access, means you cant connect anything too it like NextCloud.
Support is good, fully encrypted.