He starts to get into it right before the clip stops, but I think this is exactly why Lance is being groomed to be the QB in 2025 and why he most likely wont be the backup in 2024. I think both of these statements can be true.
I'm getting the feeling that the issue isn't that Lance can't play QB, the issue becomes that the offense is considerably different with him in the game. You really want your backup QB to be able to run at least an abbreviated version of the same offense as your starter so that there isnt a huge change for the other 10 guys on the field. Next year if they make the swap they are likely to grab a bunch of skill players who align with building the offense around Trey Lance.
My early guess here on the Cowboys plan for 2024 is that they keep all three QBs on the roster.
Dak is the starter
Rush is the primary backup that is active on game day and fills in if Dak were to miss a week
Lance is the inactive but emergency QB, also the guy who takes over if Dak were to miss an extended period of time, or the Cowboys surprisingly implode by week 8.
I just dont think the Cowboys will want to switch over to a heavy RPO, designed QB run type of offense that they havent been practicing if Dak were to miss a half of football.