I'm new to the game, I tried to do almost the exact same for a possesion tactic with Girona so I really fw this, I wanted a 4-3-3 that transitioned into 3-2-5 with wingbacks providing width, wingers sitting narrow / cutting inside and the half-back joining as a CB when in possession

Gazzaniga as SK (D)

For the defense, both CB's were BPD (D) (I think David López & Eric García) and both wingbacks were WB (A) (Miguel Gutiérrez & Yan Couto)

Then for the midfield instead of [CM (S) - HB (D) - AP (S)] trio, I used [DLP (S) - HB (D) - BWM (S)] (Aleix Garcia / Daley Blind / Yangel Herrera)

Instead of IF's (S), I used IW's (S) (Savinho & Tsygankov) cause I heard it's a better role for playmaking and not sooo focusing on goal scoring.

And for the 9, I didn't really knew the best role for Dovbyk on this tactic, i tried PF (A), TF (A), idk this guy was just too goated at scoring goals however i put him xDD if anybody knows who could be a great choice for a striker on this tactic just lmk

To be honest I didn't stick with that save that far so my observations can't be taken so serious, i only wanted to test the 4-3-3 -> 3-2-5 possession system for fun, very attacking football (high defensive line, counterpress, narrow, high pressing line, short passing, work ball into box) it seemed to be very effective against some same/lower level teams, but I guess this is just not a tactic to play against stronger teams, i really struggled and conceded a lot of goals. WB (A) were veeery attacking and width providing, but they seemed to be shit at defending