Frenkie is bad at DM and prone to mistakes. I am more comfortable with Romeu playing there and I suspect majority of people think so as well.
Not for me and dont think it is FDJs best position either.
Romeu is very limiting in midfield and slow defensively. He will be solid enough and tidy on ball and dont think Romeu is shit but think others bring more and that is not just FDJ but Gundo and Pedri also.
On Gavi... the reason he doesnt play deeper is because he is far behind Pedri, Gundo and FDJ as CM at moment and was behind them even at his best.
The best thing that happened ot Gavi was the change of formation to four mids and Xavi finding a role for him.
Since then he has played deeper for Spain and Barca on a number of occassions and been absolutely terrible more or less evry time.
Gavi needs to improve massively and stop the headless chicken/hard man act.
The likes of FDJ in season under Koeman was light years ahead of anything Gavi has shown to date.
But.... he still has time to improve and needs to get back to where was when first broke through and take it from there.
Gavi was always an AM with freedom to go hunt ball in lower categories and looks like doesnt yet know how to play CM.
Not uncommon with Barca players that AM role being hard to replicate higher up as first team dont give that freedom.. other less talented players had same issue.. Alena, Puig etc all '10s' in lower categories than dont have a role that fits fully or they are used to when try to step up.
Gavi has more ability than those two but needs to learn how to use it.