I mean, Tua's rookie season was what you see from most rookie QBs, up and down, some good and some bad.
Was it what people expected? Probably not, but that's mostly because Tua was a big star in college and that immediately added some really high (and unrealistic) expectations to his NFL career, not just from local fans but also from the national media.
I personally think our main issue this year was starting a rookie QB while also trying to make the playoffs. That was a risky move because at some point you end up sacrificing his natural progression/development in order to win games.
Add in the fact that he didn't even start from day 1, he was plugged in midseason with NO preseason action, a glaringly obvious lack of chemistry with his receivers, and an OC that clearly preferred calling plays for the guy that he replaced. (Oh, and the receivers he was just starting to develop chemistry with? They all got injured when games started mattering the most. All of them.)
Nothing about the QB switch made sense, imo, unless the goal was to give Tua experience now in order to get him prepared for 2021. And that would've been perfectly logical, except for the fact that we were trying to make the playoffs each and every week, so allowing Tua to just gain experience and grow as a rookie was replaced by "let's play it safe on offense and let our defense handle the rest".
I mean, if you're not going to let your rookie QB play loose (even if it means making mistakes and having to learn from them) because you're scared it might cost you crucial games, then why play him at all? Why not just turn to the veteran guy and let him handle that kind of pressure?
And to complicate matters even more, benching him in games when he was struggling (as most rookie QBs do) also didn't do him any favors, no matter how mature and mentally strong Tua might be.
So again, another mistake by the coaching staff in trying to "develop" their young rookie QB while also being in must-win mode, which meant having to turn to Fitz from time to time. That, inevitably, ends up causing tension and cognitive dissonance in the locker room.
At the end of the day all of those decisions have led to this "narrative" pushed by Mando and co. It would've been easier to just let Fitz handle the playoff expectations, OR play Tua in his rookie year but prioritize his development over making the playoffs. Alas, Flo wanted both and he ended up getting neither.
I still think we can fix things for Tua with a full offseason program, better weapons, AND the right OC, but the margin for error will be very small for sure.