I don't know that any late-round backup gets an incredible amount of support from the team. It's basically sink-or-swim.
I think he did enough in 2022 to earn the prime backup role when he outplayed Teddy Bridgewater. But from immediately after almost getting us over the line in that playoff game against Buffalo, we tried to replace him three times. Hardly a vote of confidence.
That said, every backup QB we had this year and last have struggled badly, not helped by receivers dropping passes, players missing blocking assignments and committing penalties, McDaniel not getting in the plays quick enough, etc. I am beginning to wonder how much (if any) of this also has to do with Tua being a left-handed passer as much as his understanding of the offense?
I think Tua must be getting close enough to all of the important reps, and any backups are getting bare scraps (or Curtis Painter-style film viewing as their "preparation" in case they are ever needed). I get that we're locked into the premise of it's Tua or it's nothing. Even though the rules in regard to protecting the QB have been significantly strengthened over the last two decades, the last time I checked this is still a contact sport and the QB is still a marked man. This is a very dangerous game to be playing with basically no backup contingency and a QB with well known durability issues.