Constructing your own tactic will only work if you put the effort in to analyze and implement incremental changes. When constructing a new tactic I will freeze frame games a lot both in attacking and defensive transitions I am looking for my player positioning in both phases, perhaps in an attacking transition we are committing too many players which means we are short defensively when we turn over the ball. There is no point blaming the CBs for a goal because being solid defensively begins at the point of when your team turns the ball over and understanding why your players are turning the ball over and where all the players are positioned when it happens.
Every-time my team turns the ball over I make a note, if there is a repeating pattern I try to find out why. Perhaps the striker is dribbling in to blind alleys and getting the ball taken off him repeatedly, or maybe the play-maker is making repeated under-hit passes or dwelling too long on the ball. The fixes to the problems can be very varied, maybe a player has a PPM that doesn't suit what I want from him, maybe the player doesn't have the right attributes so he dribbles a lot but he can't dribble or he has terrible decision making . The fixes will be anything from incremental tactical changes to adding PIs on to certain players or even removing players entirely because they can't do what I need from them.
I once took the time to play out someones Wolves save to prove to him that his tactic wasn't broken but he was indeed relying on the wrong players in critical roles(Inverted wingers) who were religiously turning the ball over when they ran in to traffic. All i did was look at every goal he conceded to see the pattern of where the ball was being turned over and why. Adama Traore is one of the dumbest players in the game, he's all instinct and no brains or technical ability, put him on a straight run down the line putting a cross in you will get a tune out of him but you can't expect a guy like him to turn in to the crowded center and do something useful with the ball. Stuff like that is why plug and play won't always work!