For me it was Outlook - I've tried loads of linux apps for mail, but if you have at least one Exchange + multiple other accounts getting 300+ emails a day, Outlook (was) the best by a very long way. My newest work is O365 based, so being able to run Edge at least once to get my profile / shortcuts across would be useful, though my browser of choice on Windows and Android is Firefox, so no problems there.
Thanks to the 365 app version of Outlook now being extremely buggy (2019 was the last good version) and the web version being okayish, that key work obstacle is removed. I may try Debian (I've used Red Hat and Debian as servers for over 20 years) as a desktop again and look into gaming more. Steam is great, but if I can also run GoG, Epic, Battle.net etc, then it may well be time.