Not arguing against the call, but it was a weird play and got me wondering.

Ball pops loose for a split second. The RB and defensive player both grab it and go to the ground. The play is dead at this point. If the ref rules simultaneous possession it goes back to the offense. They are both fighting for it and eventually the D pulls it away. As a ref, when do you say the play is over? You can't just let them fight for it forever. Do you have the leeway to determine who had "more possession" and who is just hanging on?

Another one: say the ball pops loose, the defender grabs it, then the RB gets hold and then go down with simultaneous possession. Simultaneous possession goes to the offense. But by grabbing the ball as a fumble recovery, does the defender now get benefit and become the "offensive player" in a simultaneous possession situation?