I'm testing Office with Microsoft® Outlook® voor Microsoft 365 MSO (16.0.14312.20002) 64-bits as Bèta on Windows 11 (Dev. Build 22000.51)
I choose to have the UI language of Windows in English and the UI language of Office in Dutch:
There seems to be a glitch where Calendars are displayed in Outlook:
These items still are being displayed in English.