I realize that since a macbook is a much more confined space than a desktop, it needs a constant minimum of ventilation.
But does that also apply when it is asleep?
If so I would more often consider shutting it down entirely😕
Since nothing is running during sleep, the fans are not needed. If your Mac is hot at the time you put it to sleep, it may take the fans a short time to shut down, but they will not run in sleep mode.