Accessing Microsoft Teams using organizational or personal credentials
I understand resolving this can be challenging, we have Remote Access within the Pro Management Portal which can allow you to perform admin tasks remotely. There are no plans to make any changes for 5.3 as we don't have an issue at this point only environmental causes, so for those experiencing issues on 5.2 please open support cases if you have not done so and please work with your account team's if you're not making progress with support.
I will add one additional suggestion beyond the known issues details I've shared previously; we've had two cases from customers where they have hit credential cache challenges due to their third-party identity provider, clearing the Teams Rooms cache using the action in the Pro Management Portal or locally using these steps have helped: Microsoft Teams Rooms maintenance and operations - Microsoft Teams | Microsoft Learn