things are pretty much as i had guessed: my landlord seems to own this other apartment as well, and apparently they'd offered the space to the new residents (due to an oversight wrt me and my earlier queries about the space), when i should've had priority as an existing resident 🙃 they told me they'll try and figure things out tomorrow - great!! i'm almost certain i'll have to pay for the space going forward, but again i really don't mind that now - and at least i'll actually have that space from now on! ^v^'
i just hope i won't face any further trouble because of this mix-up later on...
(also, i hear the head of the housing cooperative (who may or may not be the Guy i've mentioned before) kinda chewed the brokers out a little on their oversight, which... i don't even know their name, but lol. lmao. based)