How are everyone’s AC units doing in this heat?

Ours is less than a year old and still struggles to keep the temp at 74 (usually gets up to 78 or 79 at the hottest part of the day, even though the thermostat is set to 74). We had someone come to take a look at the system and they said it's in great shape. Our next step would be to get an insulation inspection, unless this is normal and to be expected here in the summer? I'm from up north so this is a new problem to me. Is this common?