I’m in the lucky position that I always could work with Linux. I was working with people that couldn’t be bothered to run Windows on their Desktops (administering mostly Linux Servers anyway). In my first job we had a “Standardized” Fedora desktop that was actually attached to our AD so you could log in at any desktop with your domain user. However we did have internal tools and some software requirement that only were available on Linux meaning everyone in our department had a Windows VM for using those tools (kinda overkill but ok). My last job we didn’t have any standard other than the system had to be encrypted and had Eset installed other than that we could set it up he was we liked.
Could I work with a Windows desktop? Sure I’m on the Terminal sshing into systems 98% of the time anyway but at the end of the day I love to simply be on Linux having a workflow I’m used to.
Regarding Office I was just using Office online for anything that needed it.
Getting Linux Systems into AD is possible (but of course requires cooperation on the side of the IT department)
Proxy and VPN should mostly be doable (but of course might not be able to be deployed via Group policies)
Nextcloud.
I was hosting nextcloud at home for years. Then when I worked in a Datacenter I got to host some servers there from free so I set up a two-node proxmox with nextcloud and some other stuff. Now I don’t work there anymore and I really felt the hole nextcloud left, no more notes syncing for notes, tasks, calendar, podcasts no more place to upload my photos from my phone … So now I’m hosting nextcloud at home again.
I also host jellyfin which is nice but if I don’t have it doesn’t actively hamper my workflow.