He's not No. 1 over Joe Burrow because of his injury. Tua is more proven than Burrow, who just happened to have the best year of any college quarterback.
And you know the NFL - measurables matter. Burrow is bigger and taller than Tua.
I've seen Tua in almost all of his games. And by the standard you've chosen to measure Tua, you can say that about ANY Bama player. Bama has been the standard for the past 10 years. Of course, they're not going to play anyone. When you're consistently the best, everyone else isn't and would qualify as lesser competition.
Tua has done well against most teams. The only teams he faltered against are Georgia (the second game, in which he was hurt) and the Clemson game, a game in which the Bama team was defeated in all phases of the game including coaching. No shame in that.
Furthermore, I'm less concerned about some TV pundit saying Dak is 'elite' and interested in what they mean by 'elite.' The same pundits, like Aikman, were saying Dak wasn't as great. Then when he ran into a stretch of success against subpar teams, he's elite again. And these same pundits will be calling him not elite if he reverts back to inaccurate Dak.
Be that as it may, time reveals all truth. So we shall see if Dak is elite with better coaching, and we'll see if Tua is elite or injury prone on the next level.