A weird one, which I can’t really explain yet, but wanted to share in case someone else experiences the same.
I was having these weird Outlook issues on Windows 10 when working on WiFi, but not when I was working on Ethernet. Symptoms were hanging/freezing of the Outlook app, Outlook having a hard time connecting to the Exchange server and overall sluggishness of the app. (i.e. painfully slow)
After trying the obvious (Outlook Safe Mode, recreating profile, etc.) without any success, I retraced my steps and recalled that the last big change I made tot my laptop was installing the Hyper-V role and creating some virtual network adapters.
After I removed the Hyper-V role, Outlook worked like a charm again on WiFi.
I will definitely try to reproduce this again by reinstalling the Hyper-V role at some point, but for the moment, this is all I can share. Who knows, it might help someone at some point.