Again:
Why do I reject this? Because it’s the use of headcanon and speculation to fill a gap that the writers should have filled, and which they are perfectly capable of clarifying (or not) in any way they wish for any reason (no matter if it makes sense or not) they wish. Thrall’s demeanor nor Tyrande’s is itself proof of any kind of a handover, reconquest, or other status change of Ashenvale, whose last known updates were the BFA mission tables.
Speculation is not proof - and should not be used in the place of fact. I don’t care how much you are personally convinced that your prediction is right, it is still just that.