Semedo seems improved after his recent bench time.
No player on Earth will ever improve while sitting on the bench...
The most you can say: he is hungry for his own averment if gets the chance, but that's all.
You mix up his work, development behind the curtain and the bench (which is often described as the
"electric chair" by frustrated players).
BTW, one should truly watch Semedo's bad RealM game again, because when he played against Vinicius Jr. there usually were another two players on his side, whereas the second game with Roberto was very different, Vinicius was alone, and probably he was instructed to try to cut to the middle. When Semedo faced him, he was aiming to run down to the line. Very different scenarios...
Semedo did the classical mistake with Vinicius though, trying to move too early with him, by guessing the direction that a fast player will move.
This usually happens with a pacy forward and a pacy defender. The latter moves too early and therefore can be easily beaten, whereas very often a SLOWER defender is more successful to stop him, if he does NOT want to move and remains stationary.
That's why a highly experienced (but slow) Pique is often able to stop a fast forward by doing nothing and waiting for the attacker to bang the ball into his feet...
Many defenders name it the
"mouse-move", when the "mouse" rapidly moves left and right and the best the defender (the Cat) can do is: to do nothing, but blocking his path in the middle, by not following the "mouse" at all...