A few thoughts:
1) DeShon Elliot made a mistake, and he realized he made a mistake, because he deleted the Tweet. Unfortunately for him, the Internet is forever. This does not necessarily mean that he doesn't think Tua is a good QB or that there's some locker room division. It's more likely (imo) that he saw Lamar's Tweet about requesting a trade, had a quick thought about his former teammate, and Tweeted....then thought, "oh, wait, that might look bad," and deleted it. It was stupid, but I don't think it was "cut this bum" stupid. Also, he's a pretty decent SS.
Like The Rock said to one of his clients in Ballers, "Stay the **** off Twitter."
2) Lamar Jackson is a fantastic athlete. He is an entirely different type of QB than Tua. If the Dolphins were starting over and didn't already have a roster that was tailor-made for Tua's strengths (and that the current HC is very familiar with), this is a different conversation. But they aren't. Tua is simply a better fit for this offense, imo. Jackson thrived in an offense with multiple TEs and power RB, running a lot of 12 and 22 sets.
3) Lamar Jackson is likely not going to be able to play in the NFL with current style for a long time. He's been a highlight reel his entire career, but he holds on to the ball a lot, trying to make things happen, and takes a lot of unnecessary hits. Sound familiar?
4) There are a few teams in the NFL that make a lot of sense to me for Jackson. Indy makes some sense. I look at Seattle, with their multiple first and second round picks this year, a **** ton of cap room next year, with a power run game, multiple skilled TE and a couple serious deep-threat WR and go "hmmmm." The question then becomes, so why aren't they doing it?