I have a weird suspicion that someone is stealing my electricity or maybe my maintenance person didn’t do a good job in checking my AC.

Is there something I can do to see why is my electric bill so high

Did you not follow up with another call on the phone and ask them this? It seems like NVE would have had better, more accurate answers to this follow up question than we randos on this subreddit.

At the very least you could have asked about having someone from NVE come out to investigate.

Also, do you have an equal payment plan? I'd consider getting on, so when these more expensive months kick in you're not hit as hard... even if it will cost more in the winter than usual.