Hi @DJuser ,
thank you for your feedback. I am aware of these sections in Administration part of CRM, but I think these 2 sections are used to setup OAuth for API exposed from SuiteCRM (incoming requests direction). If you want some client to be able to connect to SuiteCRM API you are setting OAuth options in this administration section.
What I am trying to do is setup all inbound email accounts to connect to Microsoft 365 using OAuth2 authentication, instead of standard IMAP basic authentication.
When looking at at available inbound email configuration options, we have following:

There is no option to enter the M365 authentication server endpoint or anything related to OAuth authentication for inbound emails. I can see Sugar has a Microsoft connector available, is something like this available as a plugin or a native SuiteCRM functionality:
https://support.sugarcrm.com/Knowledge_Base/Connectors_Integrations/Integrating_With_Microsoft_for_Admins/#Configuring_Sugars_Microsoft_Connector