From what I saw at Ajax during Erik ten Hag's tenure, when he had the double pivot of Frenkie de Jong and Lasse Schone at the base of the midfield. He didn't invert the fullbacks as much but instead had the wide forwards inverting in-field with the fullbacks providing width and hence the fullbacks were bombing forward like wingers. And it was easy to see why he would do that due to Schone and de Jong providing deep lying play-making qualities along with positional discipline in deeper roles in midfield.
Out go Schone and de Jong and the team dynamic changes with Daley Blind and Mazraoui now occupying the fullback positions as inverted fullbacks with the wide forwards holding width. Tagliafico is hence relegated to the bench due to Blind being superior on the ball in possession and hence his play-making qualities are better suited to the team as a inverted fullback or as a 3rd CB in possession. Losing de Jong meant Tagliafico lost his place in the team and exerting on the ball control meant that the fullbacks would now have to play their part in midfield aswell due to the quality that was lost when de Jong and Schone departed. So Erik ten Hag tweaked the system without compromising on his principles by maintaining on the ball dominance with the fullbacks getting involved centrally in midfield or as the ball playing CB in a 3, which Blind was very good at. And the midfield of Alvarez and Gravenberch wasn't comparable qualitatively to de Jong and Schone but the quality of the fullbacks on the ball made up the short fall where ten Hag would again develop the team to be competitive and attractive to watch.
So if the news about ten Hag wanting Frimpong turns out to be correct. Then I foresee the fullbacks providing width and the wide forwards inverting in-field. Because from the little I've seen of Frimpong, he's got electric pace and good close control to be a real threat as a winger with Antony and Rashford inverting in-field and Bruno as the attacking midfielder ahead of a midfield double pivot. Luke Shaw has potential to both invert into midfield or be part of a three man defence in possession in a 3-2-5 in possession.
I think the plan is to develop the team to be proactive with and without the ball. And having players who are comfortable in possession will allow for positional rotation and a more fluid play-style developing with the defensive and midfield lines being in close proximity to the forwards, which will create compactness and hence the pressing and counter pressing will also be more effective. Bruno Fernandes will then have the platform to take risks in the final third and will be expected to create plays that will lead to goals. And the same applies to even Frimpong (if we sign him) who will be expected to deliver going forward with players in rest defense facilitating for him by defending in 1v1 situations.
I think something similar to the below is what I'm thinking with a 424 shape in build up. So the GK and fullbacks need to be very good on the ball and the likes of Martinez, Shaw and Todibo have the technical ability to step into midfield and create both numerical and qualitative superiorities due to their technical level on the ball. And Todibo is strong at defending the channel in 1v1 situations, so he can potentially facilitate the attack minded approach of Frimpong on the right with help from Casemiro and Antony who is also very good at tracking runners.
There's different ways he can set up and having Shaw either bombing forward, holding width, or having him inverting infield or having him playing in a back 3 in possession is what is required of players within the positional play principles. You obviously need players with a high level of touch and technique along with the right attitude and personality. But you also need intelligent players who understand the principles of play.
-----------------ST------------
--LB----LW--------RW-----RB---
-------------CM-----AM-------------
------CB------CM------CB---------
I think this post possibly answers your question aswell
@Isotope