Sadly with today's auto-detecting OSes I've more than once found my audio output setting itself to speakers, or worse, to my monitor (which doesn't and has never had speakers, but that doesn't seem to matter).
The only logic I've found is that it prefers devices that handle both input and output. So, it works OK with my combined headphones + mic, but if I want to use my external dedicated mic + headphones without mic, I have to fiddle with the settings whenever I join a new call.
On Zoom changing either is literally a click away. AND you can test your mic while already on a call so you can listen while you fix your setup.
In Teams, I may have "custom setup" selected, but it'll go right ahead and pick whatever it wants.