Yes. You need to clean the build plate thoroughly after every print with alcohol. You have layers of built up plastic schmoo that is not letting new plastic adhere.

Humidity will degrade your filament too, and cause it to get stringy and warp more severely. Make sure you keep your filament in an airtight box ideally with desiccant.

Yeah mate clean the plate, I wipe my glass with 60% alcohol before every print. Most people recomend 90% isopropyl alcohol and sometimes dish soap and hot water for deep cleaning.

I dont think you have problem with too hot room, but you might need to lower bed temp a bit to get the same actual surface temp. What temps are you using? Printing pla?

Too hot bed can help with adhesion, but can cause lifting, so I print first layer at 60 and rest on 56 C for example. Big prints are more likely to lift mid print, its not bad to use brim and maybe even mouse ears. If you surface is not clean it might be painful tho

To answer your question from title:

Too hot is when your stepper driver is overheating and skipping, or when stepper motor is too hot to touch. There are more, but if you can be in the same room its not likely. Tbf using AC can only ruin your prints with uneven cooling. You want stable room (enclosure) temp

Your print doesn't come off from heat, its the opposite. If you never cleaned the build plate that is 100% the problem. I clean mine before every print.

Wipe down the build plate regularly with IPA to help keep it clean; I do this as part of my pre-print workflow. That and scrubbing the nozzle with a brass wire brush to help keep burnt filament getting into my print.

How hot is your shed? Depending on your shed temp, some filaments actually like it hot. I have a PLA filament that likes to print at 220C and in an ambient enclosure temp of 90F.

If your shed is near 120F-140F, its perfect for ABS/ASA (be mindful of VOCs); maybe consider switching filaments while its hot out - making lemonade out of lemons and all that.

cheers