Feeling gaslit by maintenance about inefficient air conditioning at apartment

I know this could be a more generic AskNYC question, but I would like BWT opinion. I could really use an outside perspective because I feel like I'm going crazy and am losing trust in my own judgment.

I've lived in my apartment for 3.5 years (on the top floor). The apartment has an older wall AC unit. Ever since I moved in, I've felt like it never cooled the apartment well. About two years ago I reported it, and maintenance told me nothing was wrong. They said to keep the curtains closed, leave the AC running, and accept that on very hot days it wouldn't cool as well. I accepted that and mostly stopped using it because it made no sense to.

This week I finally tried again because the apartment became unbearable. I left the AC at 68F for about 16 hours with the curtains closed, and it was still so warm that I was sweating. Maintenance came and agreed it was hot, and told me to leave it at 60F. After about 4-5 hours at 60F, the apartment finally became comfortable.

Today they came back and basically told me that because it was cool now, the AC was obviously working. They measured the air coming out of the unit (around 55) and said that proved nothing was wrong. When I said it wasn't reasonable to have to run it at 60 all day just to be comfortable, they said, "Do you want to be cold or save money?" They also said they keep their own AC at 60 all day, that yesterday was just a very hot day, and that I'm on the top floor.

Every concern I brought up seemed to get another explanation, like I was just being unreasonable. At one point they even brought up an unrelated issue about replacement light bulbs that I had already offered to pay for. When I mentioned consulting friends and family on this issue and they agree, they questioned me about the who and when. They kept saying how NYC has decreased the voltage.

At this point I'm honestly questioning myself. I've tried really hard not to be a difficult tenant. I lived with this for years before complaining again. I followed their recommendations. I'm not demanding a new AC, I just wanted someone to seriously consider whether the ac is performing adequately.

Instead, I left feeling like I was the problem. I understand that it is hot and I live on a higher floor, and NYC, and it may take more time to cool my apartment, but this feels a bit ridiculous.
Am I being unreasonable? Or would you also find it frustrating if the only way to keep your apartment comfortable was to run the AC at *60F* continuously?

P.S. I live in a large apartment building, and is academic housing for residents and postdocs. Which means slightly lower rent because we don't get paid very much.

P.P.S. I am emotionally exhausted and used help of AI to fix grammar and typos.