The problem is when running a sync task and the message is "Can't use this folder. To protect your privacy, choose another folder."
https://www.reddit.com/r/AndroidQuestio ... _external/
Seems that MPE client should request "All Files Access"
Here there is a workaround https://forum.xda-developers.com/t/solv ... d.4481999/
But on this Motorola Moto G52 there isn't a developer option called "Force Write Access to External SD for all Apps"
Addendum: the requests are also for "Internal Storage" and seems that selecting each folder proposed let MPE go on and sync!