I think the problem with Linux in the workplace is that it's hard (read harder than Windows and MacOS) to setup to be managed devices. Especially if the company is a Microsoft shop to begin with. The IT security teams just don't know how to enforce the company policies on Linux machines. Enforce password policy, network credentials and managed apps. It easy with Intune for Windows and Mac. Much harder on Linux.
That's the reason I was given by my work place, when I was "forced" to switch from Linux to Windows.
There is also Nextcloud Talk, but it can be a bit overwhelming to set up (needs the high-performance backend for video and stuff).
But, it's entirely self-hosted and has no user cap as far as I am aware.
What DE you like is very much dependant on your work flow and how well you can adjust to changes.
Personally, I love KDE Plasma. It's the right amount of "bling", bells, whistles, aestetic and settings for me. Gnome feels way to "simple" and XFCE feels reliable but old.
For me, the DE is often more important than the base underneath, but I do like my rolling release. :)
As a Dane, this has been frightening for years. I hope our government thinks of open source solutions, instead of just a european company over a US one.
Ho much does the screenshot you posted say, that the screenshots on the Mint download page does not? Other than giving you more options, which can overwhelm new people.
Some distro's really like doing their curated live environment for each environment, so you can test it out before actually installing it.
I ran Linux at work up until recently where I found out that they are in the process of changing the network setup, so only systems with a valid certificate can access the network. And they have no plan to support Linux in that setup. So I was kind of forced to switch back to Windows, because my work requires that I can access the local network.
Other than that, I used Linux in a Microsoft Entra/Intune environment with Edge, Teams and Office 365 for a couple of years.
Joke answer: get the IINA devs to release a Linux build.
More seriously: MPV is pretty close and might even be able to be configured to what you want. But seriously though. Sounds like you need/want exactly this UI, so you should ask the IINA devs to make a Linux build.
I know, I have used it. But it does not enforce any policies. Just tells you if you are compliant or not.
And that's my point. They could do it. Some do. But most companies, in my country at least, pick the easy solution, which is to not support Linux.