I’ve searched around and mostly seen people create custom radiator builds attached to their water supply, but that’s beyond my skill level and I’m not sure if linking it directly to the water supply via piping would violate the lease or not. Are there any solutions a bit more DIY that I could take advantage of?
OP would probably be better suited with a portable AC. Most apartments I know of ban window units because they can fall and hit people if not installed properly.
When getting a portable AC, get one with two hoses as they’re much more efficient since they aren’t blowing cooled air outside (and sucking hot air in from every gap in the exterior walls.