If your printers are set to SMTP using an account credential, then you will need to turn MFA on for that account, and create an App Specific Password and use that password in lieu of the account password.
We just completed our scan-to-email MFPs and Papercut server a few weeks ago and the process went like this:
- Enable 2sv/mfa for the "service account"
- Generate App Specific Password
- Log into papercut server and change any "pop/imap" or "smtp authentication" settings using the account password, and replace that password with the App Password
- Then log into each MFP and change the SMTP password of the account to the App Password
If you're only using aspmx.l.google.com and no authentication, then I don't imagine this would cause any impact. We however do have authentication required for 99% of our systems that use google smtp (primarily smtp-relay.google.com)