Difficulty problem in career mode

hello,

I have a problem since fc 23 on my PS5, it happens the same with fc 24, fc 25 and now fc 26. I play with legendary difficulty and everythings is fine (I win, loose or draw) at the beginning of the season.

When trannsfer period close at the end of August, the gameplay become totally crazy.. For ex, i can be in top 3 unbeaten after 5 or 6 games but as soon as the game play become crazy, i loose every ysingle game until I change the game to Ultime difficulty or If I empty the cache on my ps5, it comes back normal for a few game, maybe until end of transfer period of january. then it starts again to become crazy.

When I say the game play become crazy, I mean all my fast player are unable to run faster than any other player in the game, my Gk takes one goal per shot and my defender are unable to take the ball back.. ot's like i'am still with "authentic gameplay" while AI plays with "competitive"

 for the defender it's stranger because if I play in advanced defense, it goes well until there is absolutely no reaction with "X" but if I switch to "tactical defense, it goes again well...until it there is no reaction with O/L2 etc.. At this time, I have to switch back to "advanced defense"! In many game it's like my player move away from the ball and altough i askk my team to play very high (between 95 and 99) they are alws trying to cover ann off side and stay low in the field when gameplay is crazy but when gameplay is ok, the off side trap works perfectly 

I am really confused because if I don't do these steps (changing difficuty level to harder and/or emptying cache, switch from advance defense to tactical defense and switching again everytime it does not work anymore) the game does not works on my ps5.

I have other EA game like nhl or f1 24 and I don't need to do anything in those game but all fc games since fc23 ruin my season after end of tranfer period if i don't empty the cache.. I did a season with Mallorca, was 2nd in legendary mode after 6 games and was unable to have the gameplay backk until I had to fight for relegation. With Bayern, i am first of bundesliga before I have to fight for relegation..

What is the problem ? Is it my ps5 ? is there anybody else having the sort of problem ? The game is graphically nice but this is a serious problem