You should probably be good then, at the moment gaming seems to be the main deterrent for Linux, and yeah Libreoffice is great and works for most people, just doesn't have some of the more specialist features for some people.
DeaDvey
Linux might "just work" but it highly depends on what you use it for, gaming is getting better but is not going to be nearly as good as on Windows and there are some proprietary software that straight up don't work such as MS Office and the Adobe Suite. However programming is very good on Linux and general office tasks and browsing the web works completely fine.
Taking out the USB should let you boot into Windows without any BIOS configuration as Linux Mint isn't installed. When you install an Operating System, it gets put onto your internal storage from the USB, but if it hasn't been installed yet from the USB it shouldn't ever touch your Windows Install. In BIOS you can change the order that different devices boot if they are present. eg: USB drive then Hard Drive then SSD then DVD. So if you unplug the USB Drive then it should go onto the next device, the one Windows is installed on so that should boot. Unplugging the USB should be totally safe but turn the computer off first, I can answer your questions, I'm happy to help.
Ah, didn't know about this, that sounds like the way to go.
Making a Windows USB should be a very similar process to making a Linux Mint one, download to ISO and flash it onto a USB stick using whatever program (I recommend https://etcher.balena.io/) and if you can get another USB stick that could be pretty good or you can always flash Windows onto your Linux Mint USB once you've installed Linux Mint. Side Note: You can also Dual Boot Linux and Windows fairly easily so you can use both OSs on the same machine.
If you have another spare USB stick you can put a Windows iso onto it (I assume you know how to do this if you have a Linux Mint usb) and so if your WiFi stops working then you can boot off of that, however, I have never had any WiFi issues on Linux personally so I don't think it's a huge issue, that's just me though. Linux Mint and Zorin OS are both pretty similar for beginners other than the look of them, so I'd just go with whichever you prefer the look of. I can't really say much about the app stores though.
I have to use Teams as a student and we never even do video calls, just sharing files, and there are so many issues we have with it such as bugginess and no one understanding the UI.
I did this, then it too so long that it broke. Still hasn't been pulled.
Not specific to Mullvad, but you can use flatpak or your distro's package manager (probably apt) to install programs, On Ubuntu, you can open the software program and search the programs to install it, that should be the first thing to do when you want to install something rather than going to the website.
I just did >:)