GMail accounts with different send identities/SMTPs in front might be unusable starting on May 30th because the settings are too rigid
It seems like GMail accounts with different send identities/SMTPs in front (sending via a different domain via standalone SMTP, which will redirect incoming mail back to the Google Mail address hidden "behind") may possibly be unusable starting on May 30th because the settings are too rigid. Google mandates OAuth2 starting from May 30th. However, Geary simply doesn't appear to allow using OAuth2 for IMAP (which requires using GNOME Accounts), while using a non-Google SMTP at the same time (which requires not using GNOME Accounts to be changeable in Geary).
I don't see a basic architectural reason why SMTPs can no longer be configurable to something else just because IMAP is using OAuth2, this seems rather to be an inherent design problem with the Server Settings dialog that could be changed.
A related problem is that it doesn't seem to be possible to specify send identities/email addresses that use a different SMTP server. This for example makes me unable to send work e-mail from my phone, because while I get that through the same OAuth2-requiring Google IMAP (e-mail forward) I would need to use a different SMTP server to send it. This also doesn't seem to be available in the settings.
Affected Geary versions tested: 40.0, 43.0 (installed from distro repos)
Tested on OS: postmarketOS 21.12 (based on Alpine Linux)
Tested on machine: PinePhone 3GB/Allwinner (ARM64 touch device)