I was thinking of moving to Zoho after my Google Apps discount ends next year.
Also was considering this:
https://tutanota.com/pricing/
If you subscribe to iCloud+ then they have an option for a custom domain too:
https://support.apple.com/en-ca/HT212514
Or was looking at this, where you can basically just get your email redirected:
https://www.pobox.com/
And yeah I do the same thing, I have all my various email addresses set to forward to a single gmail account and access that on my phone or devices (and set up a "send as" so I can send looking like I am sending from any particular address).