I'm no iOS or Microsoft Teams developer so I don't have the tools to verify what is going on. But I highly doubt Microsoft and the Microsoft Teams app for iOS is to blame. It's strange that this issue seem to only occur when joining a call or meeting in Microsoft Teams, I have no issue when using Facetime, Zoom, Discord etc. But I don't think there is anything the Teams developers can do to make the Microsoft Teams app somehow behave differently when using microphones from Apple AirPods in Voice Isolation mode on an iPhone 14 Pro Max compared to using the same combination on an iPhone 13 Pro Max.