I got this message today
Your Android vitals user-perceived ANR rate is 0.68% which exceeds the bad behavior threshold of 0.47% in the last 7 days period. If your metric persists at this level, your app is likely to become less discoverable and a warning is likely to be shown on your store listing.
Improve your app quality to reduce your bad behaviour threshold. Learn more
So you never saw the message when you added more than 10 screens?
He is helping you by telling you the info is on the Google Page. Your app often doesn't respond anymore. Maybe because of all the ads extensions you used and to many screens.
Is this related to this topic where you had a project with many screens and full of ads?
You can not expect that App Inventor is able to just handle everything and then deliver a stable working application. You have to follow rules and advise given.
@TIMAI2 is a respected and very helpful member of our community. I never saw him being aggressive, so calling him that is not something I like to see.