There are live images where you can test and run Linux out of an USB, but most of those are not persistent (start from scratch once you reboot), the other option is called dual boot where you have Windows and Linux installed in parallel and you select which one to use during boot.

If you are happy to self host at her place raspberry pi with the combo: radarr, jellyfin and jellyseerr is what you want. I'm pretty sure the overseer app works with jellyseerr otherwise create icons with the shortcut on her PC. It's easier than Netflix in my opinion. But I understand if her problem is right here, right now kind of problem, where she doesn't want to wait for it to show on jellyfin.