I make a distinction between "held up" where there is no possible/probable/immediate resolution (such as a defender under that ball with players on the ground) and a fluid situation of players on their feet.
Play on the ground can also be fluid.
With players on their feet there are several possible outcomes. The attacking player with the ball may be able to reach the ground to score the try or to offload to a teammate. The defender may be able to drive the attacker into TiG or DB to make the ball dead. Or the defender may drive the attacker back into the FoP.
My preference is to allow the contest to continue to a resolution but that seems to be in conflict with Law 22.10.
That sounds very much like the nineteenth century maul in goal, which I quoted in the other thread. It was abolished in 1892 and replaced by
[LAWS]If a player when over the goal line and in possession of the ball be fairly held by an opposing player before it is grounded, the ball shall be scrummaged five yards from the goal line, opposite the spot where the player was tackled.[/LAWS]