I'm just going to wait for
@SportingCP96 to give us that detailed scouting report
Braga have done a really good job recently of developing and promoting a lot of talent coming from their academy. Carmo I think will follow in the foot step of Trincão and make a big move sooner rather than later.
At 6'5 he is quite a presence in the back line. He has a solid reading of the game and has about 2 tackles per game so far this season. Thanks to his exuberant height he almost always wins his aerial duels (81% to be exact) and so far has averaged almost a tackle a game, additionally he is very composed on the ball. At his height he is not particularly slow either, has a decent enough pace given how tall he is, He comes off as a very solid defender but he does have one thing which stands out for the negative side... He has 5 yellows and 1 red card in 8 games as he has a tendency to come in quiet reckless at times.
David Carmo was a integral part of the Portugal team that won the U19 Euros and is a starter for a Braga team that sit second in the league and have already played away to Porto and Benfica both games in which Carmo did not look out of place in.
Considering the fact he only made his debut in January I personally believe it is still way to early to talk about a move. He should earn his stripes in Portugal first and really develop his game more before making a big move that could hamper his development (See Trincao as an example, moving to Barca was a bigger bite than he could chew and he moved to soon IMO). Additionally when he inevitably is sold it will be around the same price range as Trincao as Antonio Salvador is a shroud negotiator and given Braga's upward trajectory in the last 10-12 years they can now make bigger deals. In days gone by the natural process would be moving from Braga to one of the Big 3 but Braga do not sell there best players to Sporting, Porto, or Benfica anymore and if they do they make sure those guys pay a pretty penny which typically keeps them away. (For example Sporting paid 14M for there young promising coach Ruben Amorim who at the time only had 14 games under his belt as a coach).
In conclusion he is for sure a player to keep and eye on to see how he progresses but if I was his advisor I would say to remain at Braga a while longer before making a big move. I do believe he can very likely be a starter for the Portuguese national team in due time. With Carmo, Quaresma, Inacio, and Diogo Leite, Portugal have a number of talented center backs coming through the ranks. What makes Carmo stand out in this Lot though is his height for sure. The 2 Sporting boys are still 18 so its early to tell and Leite has not got many minute. Carmo at the moment is ahead of them.
Hope this helped mate!