His heat map and shot map suggests otherwise, as well as generally watching him.
https://www.sofascore.com/football/player/matheus-cunha/886363#tab:season. I agree Shaw does not provide it, that's why I'd prefer a LB that can overlap over a winger.
Of course he is explicitly a LB, but much like Trent, he is a LB within context. He is literally given license to get into the box and behave like a winger, whilst playing at left back. If you do that, you have to have CBs and midfielders that can cover the space to allow him to do his thing. I'm pretty sure there's a quote from Marcelo that Zidane told him to "go play because Casemiro's got you covered". I just don't see us ever playing like that, certainly not in the short term, it would require a massive overhaul in personnel.
It entirely depends on how you think we're going to play IMO. I think if you have a front 3 these days, they are far more rounded than attackers of the past, unless you set up a team to cover for them. I think what he does higher up the pitch is infinitely better than what he does further back. The games we've seen him play LW and RW, he's had his most effective and best games. It's not really about the screamer, it's his all round play in that position.
What Amad did at wingback doesn't really have any impact on Dorgu though, he's his own player and not really the comparison. Dorgu had some decent games at wingback and a lot of poor ones. Every game he's played as a winger, he's been good. I want to see more of him played at winger as it's his most effective role for us and because so far, he completely deserves his spot.
Which is fine, I disagree, as I haven't seen a good game of him defending or attacking from the fullback position. I have seen him play well as a winger, against top opposition. The others you mentioned have never played well against top level opposition, as a winger. I think Nunes and O'Reilly are FBs because of the nature of Pep's full backs, they are pseduo midfielders.
My point about PSG is they dominate possession and their FBs basically are wingers, you can see from their heatmaps. I'm not sure if you're expecting us to dominate possesion high up the pitch next season, under whoever we end up getting. If we plan to go that way, we are going to need to heavily invest in CMs and CBs that can cover space and dominate possession, rather than a left winger. I can't see how we pivot from how we've been playing, to that, in a summer - unless you sell Fernandes. I don't see that happening either.
I would rather look at how well we've been playing with who we've got, in the positions they've been playing in and add to that. You seem to not rate Cunha or Dorgu long term, which is fine, but I think shunting Dorgu back to LB on the hope he'll be good and playing Cunha off the right will just cause more issues than focussing on the areas that need drastic improvement. I think you're hunting for perfection, in a system we don't even currently play.