In order to verify your app there are some things that you must comply with the key points being
Make sure that your homepage meets the following requirements:
- Your homepage must be publicly accessible, and not behind a sign-in page.
- Your homepage must make clear its relevance to the app you’re verifying.
- Your homepage must be accurate, inclusive, and easily accessible to all users.
Make sure that your app's Privacy Policy meets the following requirements:
- The Privacy Policy must be visible to users, hosted within the domain of your website, and linked from the OAuth consent screen on the Google API Console.
- The Privacy Policy must disclose the manner in which your application accesses, uses, stores, or shares Google user data. Your use of Google user data must be limited to the practices disclosed in your published Privacy Policy.
As well as
Prepare a video that fully demonstrates the OAuth grant process by users and shows, in detail, the usage of sensitive scopes in the app.
By the looks of the messages that you are getting you have not verified your domain or set up the privacy policy or sent them a video.
Application verification can be a little confusing thats why i put up a video dedicated to it. It may help you set things up What you need to know about Google verification in 2021.
Additional reading OAuth API verificaiton