I got you. The main point that BC left ball intentionally somewhere for it being picked up and there was no legal handoff or legal backward pass
Essentially, correct. But “somewhere” has to be in the vicinity of the snapper, which, unfortunately, is not defined. In your diagram, it appears that, after the snap:
-A30 laid on the ground behind the left guard, then
-A10 placed the ball on A30, but not in his player possession, then
-A45 crouched over A30, to conceal the ball, then
-after a second or so, A45 grabs the ball off of A30 and advanced the ball.
And all of this happened more or less behind the left guard.
I’d have a foul for a planned loose ball in the vicinity of the snapper. 5 yards, previous spot, LOD.