I have the premium plan for and vpn and password manager benifits and use it for college work, game back ups, and saving and sharing unhinged video game clips with friends
I use libre office myself as well with proton drive so I can pull up all my .doc and .docx files on my iPhone (ik very privacy focused /s)
Also the other user mentioned obsidian I like it too. I use more like OneNote kind of notes for my college classes be it typed or hand written (with the Excalidraw plugin)
I set my obsidian save location to proton drive so I can hand write my notes in class then pull them up on my big monitor on my home computer
Sometimes obsidian will cause proton drive to freakout due to obsidians auto save feature (nothing bad it’ll just stop syncing) so I just pause proton, do my thing in obsidian with it saving but not syncing, then just resume the sync
Sometimes they’ll play nice together but other times not so idk¯\_(ツ)_/¯