How to remove all the chat app settings and start over

I have previously set a chat app,using manual configuration (the only available way at the time). For many reasons, the chat app doesn’t work any more, the GCP doesn’t exist anymore,and I also changed the ownership account of thr app

Now,I can’t reset or delete those settings in app, it looks like they’re permanently saved.

Does anybody know to to remove (not just disable) it?

Where in an app can I find the google project number I have saved for chat app? I can not find the GCP number field that is mentioned in the troubleshoot page

When using manual configuration, if the Google Project Number field configured for your app, does not match the Google Cloud project number associated with the configured Google Chat API. In this scenario, the following error message is displayed:

Request failed (Code: 2). The GCP project linked to your app does not match the GCP project of this chat app

Update the value in the Google Project Number field to use the correct project number."

I am also waiting for a solution from the support team, other than delete/copy the app and start from scratch.

Thank you,