I'm on the East end of the heat dome Millcreek is under. There haver been a ton of articles locally about cooling, energy use, etc. floating around this week. One of the HVAC companies was suggesting that heat pumps are designed to optimally work within 20 deg of the outside temp - that is, if it's 100, don't expect it to get you below 80 efficiently.
I'm still fairly new to heat pumps, so don't know how accurate that is. It has been around 100 here the last few days, and it doesn't seem like the heat pump is working that much harder to keep me at 74, which is what I'm running during the day while this heat wave is on (ceiling fans are on). My energy use graph from the power company shows some increased KWs for sure, but still not approaching what I see for usage in DEC when it's 30 outside and I have it set for 69.
I've been setting it to 71deg for night, and I've seen it struggle a little to get from 74 to 71, which it doesn't do when I change temp like that when the highs are in the 80s. It's around 85 outside when I set that around 2100.