[Building a tactic for my squad [FM22]]

Looking at your squad, I have a tactic that I use when I want to overwhelm a team (though used in small doses for reasons that will be apparent once you look at it!) The only thing that may let you down is your Left Back.

It's a 2-3-5 (W-M basically) based off of how Pep likes Man City to be in possession. 

I play a 4-3-3 normally, with Rodri in the DM role, Kimmich at RB and Cancelo LB - with this variation I move Kimmich into the DLP role, Rodri into the DM role and Cancelo I tend to move into a Segundo Volante role but in that screenshot it's a little more defensively thought out, well, as defensively thought out as it can be when it's used to push for a win!

If you can get hold of a LB capable of playing in a DM role like you have with Menino on the right then that could be a good option to maybe start the first 10-15 mins to push for an early goal, then switch into a more traditional 4-3-3, or the last 10-15mins of a half/the game to put pressure on.

Obviously it's a high risk, high reward variant to use but i've even left that tactic on for a whole game on a few occasions and walked away with like 9-2 wins etc. - again, with the caveat that it is Man City so obviously OP but one that i've also used in a similar capacity with Middlesbrough, who are anything BUT OP (though I wouldn't even DREAM of playing it for a whole game with them!)

[Player positions make no sense and never have]

To be fair, as Michael has said, it sounds like you could be encountering a bug. 

I've managed to retrain Natural Full Backs to Wing Back and Right Midfield Roles, and a few into Right Attacking Midfield Roles (mostly with Regens for that one)

I've converted Centre Backs to Defensive Midfielders and Vice-Versa, Strikers into Central Attacking Midfielders and Wingers, and Vice-Versa.

It's mostly done by setting their Individual Training to that Position and Role - so a Right Back you want to convert to Right Wing Back, then you need to set their Individual Training to Wing Back in the Right Wing Back role. Then you need to play him in that role regularly for him to gain even more familiarity.

In my Middlesbrough save i've got Djed Spence and Isaiah Jones both comfortable playing anywhere from Right Back to Right Attacking Midfield (Winger) and converted Martin Payero to play initially as a DM in a Segundo Volante role and then into an Attacking Midfielder (Support) and the AMC position 

[Sports Psychology Staff Addition]

Sorry if this has been previously suggested, but I thought that the addition of a Sports Psychologist in the Backroom Staff could be something useful to add into the game.

We all know about the hidden attributes of Consistency and Important Games, as well as things like Professionalism. Perhaps with the addition of a Sports Psychology Department, or simply Sports Psychologists, they could be used to - over time - improve those Attributes.

Sports Psychologists in real life are used extensively among top teams, not only in Football but in most Professional Sports, and that 1%-5% difference they can make is huge