You're vastly underrating Semedo here.
Bar that one bad game, He's vastly superior Roberto in 1v1 duels the most and that's crucial in away games this season. There's a good reason why Valverde has opted to use Semedo in CL away games than Roberto while Roberto is only being used as an RM for the most part.
Not really a knock on Roberto as he's suited in other ways. Valverde realized that playing Roberto in away games with teams that press with fast players can hurt us big time and it's important having Semedo on that RB in games like that.
I agree. He’s probably the best 1v1 defender at the club.
He did have a rough time against Vinicius, but so what? Are we supposed to forget that he usually neutralises the wingers he comes up against because of that one game? He’ll learn from it,
Ashley Cole was an excellent one on one defender. Yet he got absolutely roasted alive by Joaquin in a Spain-England match. It happens.
I actually think the RB position is pretty well covered. I do think Semedo has shown improvement and is a better fit to make the position his own, but Roberto has largely done well too.