I'm still using this in the full release with Everton. January of my second season and i'm sitting third, so at the moment the tactic is definitely still working for me, all be it differently than before.
Gone are the games in which i'm scoring 4,5,6,7 goals... and instead there are lots more 2-0 and 3-1 wins and more clean sheets overall.
One thing I have noticed with FM21 is that the PL is extremely competitive. This is probably more realistic to be fair. In previous years I think it has been too easy to win the PL. With Everton I have only lost 1 game in 20 and i'm 3rd, which is harsh, but it seems realistic that Liverpool, Man City, Man Utd might also not lose many games at all.
I also have trouble after a defeat, avoiding a huge slump! At the end of the last season we were 2nd/3rd all season and then finished 5th after an awful April/May where I could not life the team and we lost at home to Burnley for example. You have to be so careful with player morale and motivation or the game will destroy you.