My bedroom door has a lock on it and the key is stuck between a 90 degree turn and the top (pictures below). The weird thing is that when I turn it counter clockwise it moves the latch bolt just a tiny amount and then gets stuck again. I’ve tried turning the handle while attempting to unlock or remove the key and everything else I could think of. I really don’t want to have to call my landlord just for a locksmith to come and fix it in 10 seconds because of something stupid I couldn’t think of. I’ve never seen a key/lock get stuck like this before so all help is appreciated, thank you!
That looks pretty much like a standard Euro Cylinder.
On the face plate on the edge of the door, about the height of the cylinder, there should be a cross-head [Phillips] screw. Release that & by jiggling the key in the lock you should be able to pull the barrel towards you & clear of the door.
That will at least let you get a slightly better look at it. They're a bit monolithic, so there's not a lot you can do with them if some oil & a poke doesn't do it. They're not worth trying to split. If you do need to replace it, you can get new ones for as little as $£€ 10 [more for higher security].
While you've got the barrel out, you may as well have a look at the actual lock mechanism & make sure you can move it easily. You might get better access with the entire plate off the door edge… but you might not. Some are easier to deal with than others & you won't know til you start to open it up.
Getting to all this is pretty simple stuff. It's only once you get to the innards you face issues. Mostly locks aren't 'user serviceable' so don't bother if oil & finagling gains nothing - just replace.
A locksmith will, of course charge you more like 70 to just change the barrel, so it might gain favours with the landlord. Have a word.