Both qbittorrent and 7zip are FOSS projects that are perfectly available on Linux. There's actually very few software packages that aren't also on Linux, but they have a strong pull. Like AutoCad, Photoshop, video editors, DAWs, etc. Is specialized niche software, not everyday software that usually stop people. Also, they are unfamiliar with a workflow to do certain things on Linux's DEs.

I'm somewhat of a creator myself and I mostly use creative software that has Linux versions (will move to Linux once Win 10's support expires and/or I somehow get enough money for a new PC), and they're legit better than Adobe software for my usecase. Photoshop is nearly unusable for digital painting (it's more of a photo-editing software with some drawing capabilities), Krita is pretty good, and my only pet peewee was that some of the brush compositing modes had confusing names and were hidden deep inside the menu, but then I found "greater", which can somewhat mimic the behavior of the default CSP brushes.

Also can someone recommend me a guitar amp modeller (preferably an open-source one), that is available on Linux, so I won't suffer from both the demo of Guitar Rig came with my Arturia Minifuse, or with trying to get one running in Wine with all their complicated copy protection schemes?

I'm probably an outlier lol, I installed the Windows version of 7zip (via wine) alongside the native Linux version just to have a GUI for setting the compression parameters if I'm creating a new archive from the file manager