Controlling settings, permissions, and membership within Teams and channels
Hi,
I had exactly the same issue: new Win 11 install, everything set to US English, Teams appears in German.
What helped was the first option of Stephen's post, slightly modified:
In Teams settings "Appearance and accessibility", it was set to English US already. Still, it appeared in German.
So I set it to German, hit "save and restart", opened settings again and set it to English US, save and restart again.
Since then, Teams display language is English as it should be.