I am in the same situation.
My little company gives a TV a google account, we add some scripts to that accounts GDrive, and our clients can then control pictures / videos / scrolling text that is displayed on the TV simply by sending an email. It is basic digital signage with no CMS software to access or learn.
I have hundreds of clients and they all got this message and of course all panicked.
I panicked as well.
This is what I think I have figured out.
Because it is gmail based I will see an unverified app warning when I set them up an
and will have to go to the advanced tab to authorize it.
There is a limit of 100 users per app. Because I only have one user per gmail account there will be no issues.
If someone wants to have more than 100 users they have to get verified (FOR A FEE!!!) or asked to have the user quota raised.
Quoted from another page buried deep within the bowels of this Google document trail:
Who doesn't need to fill out this form?
Don't submit a review request if any of the following applies to you:
You'll only request OAuth tokens for your own accounts and not from external users.
You’re using the app to send emails through WordPress plugins or similar single-account SMTP usage.
Non-Apps Scripts Web Clients: If the users of your project belong to the same G Suite domain, and the project is associated with a Cloud Organization.
Apps Scripts: If the owner and users of your Apps Scripts belong to the same G Suite domain or customer.
You don’t need to fill out this form or go through the verification process. We recommend that you continue to use your app with the unverified app screen intact. See this FAQ for more details.
However, if you want to remove the unverified app screen, you will need to submit your app for approval."
So.... I am thinking correctly or is my stuff going to go BOOM in January?