Him playing behind Bruno would mean he's deployed in a double pivot which I feel might be a tad risky at his age. He's got a fantastic work ethic but I think his defensive game is still evolving and not quite to the level required to play in such a position which requires a lot of discipline and maturity. So if Solskjaer tried it, I'd be intrigued to see how it goes but it would probably have to be against a so called lesser team and it would make life easier if we had a midfielder next to him with a strong defensive game. And I don't think we have that midfielder. But if we did have that midfielder, who has the defensive game to provide a platform for the midfielders like Mejbri, then I would hope to see us change formation to 4-3-3 whilst resting Bruno and having a midfield of Declan Rice as the DM flanked on either side by Pogba and Mejbri. But unfortunately we don't have that midfielder sadly. And Declan Rice playing next to Pogba and Mejbri wouldn't need to be great at passing the ball through the lines.
But having said all that, I feel he should be deployed in a similar way to how Spain used Pedri in a 3 man midfield with Busquets as the most defensive minded midfielder.
Yeah, I do agree with most of that, but he cannot halfway house it at lower levels anymore, which is a problem because he needs games at a higher level, but, imo, also needs the protection of a club whose voice carries serious weight to put referees on blast who don't keep the game fair when it comes to the hits he receives.
There's 'toughening up', and then there's taking the piss with negligence of duty (doing your job as a ref!), which is what worries when a talent of that level plays against cloggers he is routinely making a fool of. At least if he's in the PL, he should be earning cards that put opposition in jeopardy for a repeat hack unless systematic rotation of offenders, which he's not worthy of until established as a serious threat in the division.
The formation and personnel issues you've mentioned are concerns, but it feels like we've got to work something out and not limit his development. The positions you mentioned are the worst of all to try and break into, however. Bruno plays a lot, and even when he doesn’t we can put Pogba or Sancho there, injuries permitting. Same goes for the left flank - it's just about our deepest attacking position, so he's unlikely to get anything but cup minutes there, if that.
He needs more than a handful of games, and with that said, would you ever consider a loan being the best thing for him? If yes, where would you like to see him go, bearing in mind we'd want him playing as often as possible.