We went back to the office, I don't care because my commute is immaterial BUT now I leave my laptop there, I disassembled the workstation at home and packed it away, I will not work at home now. Teams is on my phone because I don't put the work email on my phone and needed a way to tell my team if I will be unexpectedly delayed. I don't open it ever though, and now we have a group text might take it off too.
They have the ability to turn off the web access now. My company recently did just that - if I try to access office.com on a personal device, my log in is blocked. Works fine on a company controlled device.
I'm not sure how they tell the difference since it's through the browser. But my guess would be something to do with the lack of all their security software they load onto company controlled computers that have hooks into everything.