This appears to be a persistent problem. The Samsung Galaxy S22 Ultra that I own. I had no trouble connecting my Bluetooth headphones until recently. I can’t now. Sony Wh1000MX5, NuraTrue, and my AKG. Everybody fails. My phone app does not have a setting that lets me select my headset, unlike the PC application.
You may try the other options below. Hope that one of the solutions will solve the issue.
1. Check also the apps permission on your phone like camera, microphone and also nearby devices.
Go to Settings -> Apps -> Teams -> Permissions -> Allow access to “Nearby devices”
2. Try to connect with your bluetooth device first before you open the Teams.
Please let me know if this doesn’t work or if you need further assistance.