Zoho and PM have two entirely different reasons for existence. If you don’t want E2EE (assuming the other sender is on PM) then by all means, use Zoho. And IMAP isn’t E2EE compatible in the slightest, what they’re charging for is the decryption bridge that makes it work with an IMAP client. They had to come up with that, it’s not just a switch you flip at PMs end that makes IMAP work.
Zoho and PM have two entirely different reasons for existence. If you don’t want E2EE (assuming the other sender is on PM) then by all means, use Zoho. And IMAP isn’t E2EE compatible in the slightest, what they’re charging for is the decryption bridge that makes it work with an IMAP client. They had to come up with that, it’s not just a switch you flip at PMs end that makes IMAP work.