Yeah, I have been playing a 60+ hour game. Concerts and stuff cost far too much stamina. To counter it, I usually just hire more idols but this causes me to become less attached to my idols and its a bit of an unnecessary strain on the grinding part of the game. I just wish the sauna was much more effective.
I do the same thing! Plus, the more idols I have, the more Medical and Break rooms I have to build. I built a theater once, but all of my idols' physical and mental health deteriorated to the point of being unable to promote or perform. Hopefully, we'll have another way to increase physical stamina because it's tedious rn.