And for a few weeks during summer, it is super nice and cool so you can cool off and sleep.

For years I have thought about getting a small portable AC unit for the summer so that I can pre chill my bedroom before going to bed, but every year I feel it is too expensive, and keep using the shower and a sheet to cool down

Portable AC units are trash anyway: youtube.com/watch?v=_-mBeYC2KGc
Portable Air Conditioners - Why you shouldn't like them

YouTube
Mono block units are, yeah. However some split units have appeared on the market in recent years and they are great for people who rent an apartment without any AC. I bought a Midea PortaSplit last year and it’s amazing.