Mac Mini M4 Overheat while in sleeping mode

Not sure anyone came across the same, when my Mac Mini runs into sleep mode, the console becomes quite hot. When I activate it again, starts to cool down. I even tried closing ALL the Apps and also the only thing running at the background is the Weather Widget, but the problem still remains. Visited the Apple Store and they could not quite find the reason and suggest to change the montherboard/fan etc. BTW, the guy actually said the fan is working fine, no other defects on hardwares after some testing.

I went back and tried a TP apps called iStatistica Pro, from the recording, I guess I might have found the reasons for it. I noticed the fan actually got turned off after a while, hence temperature gone up. When I wake up the mini, the fan is back on again and at the beginning, spinning at a rather high rate too.

Then I do some more research and seems one thing to get around it is to toggle on "Prevent automatic sleeping when the display is off" under the Energy option in Setting. The way I see this is somehow NOT letting the mini to sleep, so fan keeps spinning. After doing that, I would say the temperature seems reasonable.

My questions :

1. Does the above make sense to others?
2. Also, if such toggle means basically keeping the Mac Mini awake and fan keeps spinning as long as the power is on. Is it good to keep the fan running like that?
3. Is there other way to keep the temperature in a reasonable range while really letting the Mini to rest?

Thanks everyone for your help.