Generally agree with the rest, but it seems like where we're going next season is the following:
Onana, Shaw, Martinez, De Ligt, Dalot, Mainoo, Ugarte, Bruno, Garnacho, Amad, Hojlund.
(The attack could be constructed in other ways esp. with Zirkzee but I went with a Wide creator, inside forward, #9 for this example). Build up (3-2 structure) I assume will look something like:
------------ Ugarte ------- Mainoo ------------
------ Shaw --- Martinez --- De Ligt ------
De Ligt and Shaw will have the license to carry the ball and will defend the wide spaces in transitions. Both are really good at this - Shaw because he played LB and De Ligt because he did that for the Dutch team for example in a 3-5-2.
I think it will work just fine esp. with the role you outlined for Mainoo but curious to get your take.