Why can't I manage to play an entire tournament consistently well at fifa?

This question doesn't answer something mega important for my life, but it just interests me.

Well, I really like to play fifa on ps4. And I always play a tournament (e.g. Bundesliga). And it struck me (regardless of which fifa series and tournament) that the course of a tournament is always the same. No matter which league and which team I play, I always end up in the middle of the table. Very often I play sensationally draws against top teams (e.g. With Stuttgart against FC bayern) or fight for a victory. But the game after that against actually weaker teams (e.g. Victory at FC Bayern and the game afterwards then 0: 4 home defeat against Mainz) I get the clap. I always have such a low in the middle of the season. I have the feeling that my players have forgotten how to play football and then I'm always totally torn apart by teams that are actually worse than me (e.g. I lost 6-0 to Düsseldorf) and that's just the way it is every time.

then i'll never make my tournament goal. Is it just like that for me, or has fifa set it like that and is like that for everyone.

Only when I use a top team in a lower-class league (e.g. Real Madrid in the 2nd Bundesliga) will I take everyone apart and also win the tournament confidently

It's the same for me, playing a coaching career with Hamburg.