@beeshyams Nothing funny about that. The API was there before, true, but it wasn't enforced before. It's enforced only for apps targeting SDK30+.
It would also be interesting to see if those restrictions apply to su via a terminal or adb shell. If not, there should be ways around it for "root apps".
But OTOH I'd wonder that developers of a "root filemanagers" would have missed that, and upgraded to SDK30+ nevertheless/untested.
@Izzy I just replied to your comment under the question. Yes, they are aware of consequences and IMO, poor judgment not to mention this in app description
One developer wrote to me and simply said Android 11 restrictions is the reason (responding to my poor review)