Darnold, however, appeared to hit his ceiling at the end of the season. His final two starts were his worst, as he threw a combined 23 off-target throws and took 11 sacks as the Vikings lost games to the Detroit Lions and Los Angeles Rams (in the playoffs) by a combined score of 58-18.
https://www.espn.com/nfl/story/_/id/44100716/vikings-unlikely-tag-darnold-hope-sign-him
The dolphins should take him. Tua is good vs lesser opponents, but he'll never win a playoff game, let alone a super bowl. And he's injury prone. He'll be out of the league in the next couple years.