Hi Filip,
I am familiar with most of the commonly sold Xerox models in the US and none of them support OAuth natively. OAuth is not authentication it is authorization, and that's an important distinction. I'm not sure if/when we might see support for Authorization services in addition to the currently supported Authentication methods. The good news is that most if not all of the services that you mentioned still can be configured to accept SMTP Auth for individual accounts and all Xerox models from the last few years support STARTTLS 1.2 as required by those services.
Gmail/Gsuite utilizes app specific passwords for accounts that no longer display the options for 'allow less secure apps'. Use the app specific password instead of the normal account password when configuring SMTP on the device.
Office365 admins can enable SMTP Auth on a per account basis for the sending email accounts. This can lead to some confusion though. For example I assisted a customer recently for a new install of a Xerox PrimeLink and VersaLink printer. Scan to email was failing for authentication. When we checked the settings for the account that we were using SMTP Auth appeared to be enabled but it actually wasn't. Their was a companywide policy enabled that disabled SMTP Auth for all accounts, but it didn't change the checkbox because it was applied after account creation, after we disabled and re-enabled SMTP Auth for our account email submission worked from that point on.
OAuth is great, and it has many uses, but it's not ideal for use on MFD's currently. OAuth access tokens typically default to being valid for 60 days I believe. You'd need a mechanism to get new tokens on all of the devices that are authorizing with OAuth. This is among the primary reasons why I don't expect to see it replace SMTP Authentication, with good encryption, on MFD's any time soon.
