I’ve raise window and turned ac on at different time. The temp on the one gage drops while the other slowly drops. Thinking maybe getting another gageYou dont have a room to yourself? Which is completely fine-- I'm not judging. But if you do have a room to yourself, can get a window or portable ac unit to cool down only the room. They need a nighttime drop. Not providing proper temp drops will only stress her out more and more over time.
76 degrees at night is quite hot for even the day. The daytime ambient should be around 70-75. 76 falls above this range. How hot is your room getting during the day? If you don't feel comfortable answering, that's fine. But you need to get an AC unit of some sort to cool the room asap!