They have full control over your device. It's the same for Whatsapps encryption, where Facebook can still access everything on your decrypted client.
Salzkrebs
After a few years of philosophy in university, I think it's like software development. You can always go to a lower level but doing so won't bring you forward in most cases. You can ask these meta questions on every single argument but there are no satisfying results. Don't get me wrong, I still think it's fun :D
I hate searching for sway config stuff using DDG (which returns Bing results).
Chances are never zero that that there is an outdated MS product with the same name of what you're searching.
Since I live in the EU, it shouldn't even be legal to force students into Discord. I really hate being that guy but if they do this shit again I will refuse.
My university forces its students to use Discord for computer science. They even forced me to use my real name (otherwise they would've kicked me from the channel). It's a privacy nightmare so I hope they will switch now since they were using it to host weekly exams.
So you manage your own encryption keys for cloud files? Thats pretty much the only way and even then you have to trust Apple because it's closed source.