I don't think Bruno Fernandez will playing well when his position moving to be winger because his real position as attacking midfielder, actually between Mason Mount and Bruno Fernandez have the same position as attacking midfielder and not good ideas when put each other in winger position side, but Manchester United have many attacking or holding midfielder right now and less position in winger. After Jadon Sancho withdrew from main squad only have Marcus Rashford as real winger position but he still on the top performance right now.
Upcoming match in Premier League, Manchester United will face Crystal Palace again after winning in EFL Cup and seems not difficult for United get another positive result and three points achievement.
You're right, Bruno Fernandes might be able to play in the flank, but he'll not be at his best cause he doesn't have the pace to put the opponets wing back on the run, therefore if Eric Ten Hag wants to see the best of Bruno against Crystal Palace, he should play him in the attacking midfield role then play either Mason Mount or Pellistri from the right wing, Mount is also a versatile player and he's got the pace and can put a cross to Højlund from the wing.
Manchester united are not completly out of options when it comes to wingers cause Gernacho could be used in place of Rashford, he played full time against Crystal Palace in the EFL and performaned very brilliantly therefore i think Erik Ten Hag could consider starting Gernacho in place of Rashford since he's not performing very welĺ yet.