EAFC25 players changing tactics

Hi, i have got back into playing fifa this year and i dont understand the tactics   ive tried so many combinations to make my players show themselves for passes and make runs in behind however half way through the game they will just start standing behind the opposition and faking me with runs and then stopping as i play the ball   i’ve tried tonnes of tactics on youtube but it always seems to work early on then later on in the game my players just won’t bother anymore and the opponent will score 3 in the last 30 mins and take the win  i thought it might be fitness but they were all still on green fitness apart from my CBs   any help would be great as it’s ruining the game a bit when i’m playing well and they all just stop