As I was forwarding emails to Gmail and reading them with their IMAP, I just stopped forwarding and set up a custom mail server with hmailserver. But this does not solve the problem of people that needs to access emails sent directly to Gmail address.
But Thunderbird out of the box. Strange...Yes, same set up here. Forwarded a bunch of other mail provider's accounts to Gmail main account and access them via IMAP. I built a OAuth2 module in C# and just need to insert it into ZP. This should solve the issue.
Oddly not even MS Outlook (the standalone software) support OAuth2But Thunderbird out of the box. Strange...