Ok. I see what you mean, and I have observed things similar to that. Now, read the following, and you tell me what you think.
Consider a player, P1. P1 is a 5 star 'nordgen' listed in the auction market.
Team A buys him. In his first season, he performed poorly. In the next season, he was poor again. Team A puts P1 on the auction market.
Team B - a team from the same level as Team A - buys him. In his first season, P1 performs well. In his second season, P1 continues to perform well.
A possible explanation: there is something that regulates how a player will perform for a particular team. The switch is done after each transfer. Taking the above as example, P1 was made inferior significantly (decreased in % efficiency or something else) when he was bought initially, but he was made back or closer to his visible quality after the second transfer. This switch could be a random switch.
Now, lets talk about 'team chemistry'.
Do you think there could be such a thing as 'team chemistry' in this game when you yourself have agreed to a certain extent that the age, the preferred foot, and the nationality of a player are just visual, that is they have no effect in terms of performance of the player?