With 18650 Li-ions, you only need to concerned about charge level if they're going to be stored for three months or longer. Then it's recommended they be left at 40% to 60%.
Unfortunatelly, two conflicting opinions about battery storage
Searching a bit on the web you will find someone suporting your favorite theory.
That's the reason I decided to be conservative. If storing at 50% is good for a long term storage IT CAN'T BE BAD for a short term storage.
In my case, It's a matter of caution. Mavic Mini batteries are like gold for me. Impossible to find a reemplace nowadays due china medical crisis.
For me that applies both aircraft and controller batteries.
You have to make your own decision...
R.