Accessing Microsoft Teams using organizational or personal credentials
I was having the problem yesterday, and no troubleshooting options on the app itself would work.
I then went to Teams on my desktop and added some posts and configuration to a new team that my network admin had automatically set up. After making those changes, the iPad app launched without crashing.
I can't say for certain that interacting with that Team on the desktop app is what resolved the problem, but it's the best info I have.