Top 3? That is mighty high praise. I think Mahomes, Hurts, Lamar, and Burrow would be rated ahead of Tua right now.
I disagree. Though Tua has an injury issue that holds him back from reaching the type of QB he could be, when he is healthy only Mahomes is without doubt better and more effective, while Burrow is arguably there ahead of Tua because of consistency, but on potential is still imo, to be decided if/when Tua proves he can play without getting badly injured.
Jackson is a great dual threat QB, but if you can slow his running down, and is forced to be more of a pocket passer, he can not hang with Tua in a shootout (Example: Last year). As for Hurts, almost the same story, with a bit more effectiveness in the pocket if need be.
I don't put too much stock in dual threat QBs that tend to run 1st, or may not show the discipline to stay in the pocket a bit longer. Jackson and Hurts are great QBs, but running comes with wear and tear, it hinders the chance of a big passing play because the QB was not willing to wait, and if the QB has to run too much, it will slow down an offense in scoring, so if the offense falls too far behind, they will make it tough to come back.
I also believe Tua is more accurate, with better anticipation, and a quicker release, then both Jackson and Hurts, as well as also having as good or better deep ball then both of them.