On the last count, Unix and Unix like systems run ~85% of all computing environments. If 8.5 / 10 environments are going to be Unix or Unix like, then you have an absolutely solid stance for demanding Unix / Linux support.
School, you don't have to use their software, I don't know why you think that would be the case. If the school wants you to use program X they need to provide it, period. Now, you fairly said the school did provide X and Y for you, so fair enough, but if they want you to use T, U, and V, then either they provide them, or they fuck off.
When I had to run Matlab, the school was told they either buy the Linux license for it, or I'll run Octave. I ran Octave. When the school demanded I use MS Office, they got a big old fuck off and I used LibreOffice. One professor got her panties twisted over the fact she couldn't open an ODF document, while, that's her fault, not mine. She also got mad repeatedly that I would sign my documents with PGP, and send her the signed version. She tried to fail me, until I pointed out the large block of text about accountability in the school guidelines. By signing the documents I created a source of trust, and either she had to propose a better solution, or deal with it, she dealt with it. That was actually a hilarious situation, because the school couldn't force me to violate myself, or the guidelines, so the school's overeager language and terms, created the problem, and the solution.
That same language about accountability, is why I refused to run Windows, MS Office, and all various platforms that were, and are still, digital molestation all stars. If your professor tells you to jump off a cliff, do you do it? A school or workplace can't force you to violate yourself, running platforms that do that violation is no different. Realistically, how much of a headache do you cause people? The file format is different? They have to install an extra application or two? It's not that much of a disruption.
This week, I've had Microsoft and Atlassian join Jitsi calls, after I outright refused to use Zoom and Teams. Last week, I had a large company hold a meeting on Jitsi, because I refuse to use Zoom. The week before I had the company board meeting over Jitsi, again, I don't run Zoom. You don't need black magic or to be the “My Pillow” guy to have standards.
There was one software in my Telecommunications Engineering class that was specialized, and couldn't be substituted. I don't remember the name of it, and it was closed tighter than a nun's nasty. It only ran on Windows, and you required like 4 licenses to load it. In that one case, the school was forced to provide the computers, and the licenses. It had no alternatives, it did something very specific with telecommunication simulation. That was, and still is, the only package I have ever given ground to out of force, since grade 7. In grade 8 I forced my primary school to put a computer running Linux in the classroom, that was in 2000. Seriously, you don't have to bend over and take it. I have my work place provide a phone just so I can run Slack on my off hours!