WhatsApp is the de facto default messenger even on iOS and despite having to go the AppStore to install it in most of Europe and South America.
The situation has a lot to do with Android not bundling a default messenger. So yes, competition authorities are very much right to be investigating bundling. It’s a real attack against free and fair competition.
Plus it’s not like you are not actually paying for Teams in your subscription. Actually you are even if you don’t use it which is silly. Products should be sold by themselves with a proper price tag.