I spent a night in EY F lounge in AUH a few yrs ago. no doubt things hv changed, there is a hotel airside And I’d be disinclined to repeat this. Anyway me and the much better half checked-in one eve, her for 10pm flt to Syd or Mel, me for 9am next morng flt to Sin.
Some concerns at check-in about the differences in Itins which I sought to answer by saying that, because we were travelling separately, I wanted to see my wife safely away and would be happy to stay in the lounge. I think that explanation was key.. It took a 20 min reference to adjacent Immig authority but we were allowed thru and upstairs to the F lounge, where we had dinner, I saw the BH off to her gate, went back to the lounge for a bit of work, a bit more red and then, with the lounge services closing, occupancy of a room opp the lounge desk, a quiet room with a long comfy couch, pillow and blanket. Staff had said there was a 4 h time limit but nobody came near me. Got up at 8 ish, had a shower, breakfast and was ready to go for my morng trip to Spore.
But that was a particular circumstance and years ago. With age I now doubt I’d ever want to spend that length of time in one place, unless there was a proper room and a bed attached..!