My house is more than 100 years old and has a large insulated attic you can stand up in, no crawl space.
One 15k btu AC for the living room and 8k in the bedrooms works OK for now. Half the time I run them in dehumidify mode rather than cool, it is only the 80F+humidity days that get to me.
The home automation I would really like is a “summer night” mode that around 10pm would open all the windows, turn on all the fans, and let the cool summer night air circulate, then seal thinks back up at 9am.