Stamina is definitely huge part of decreasing agressivnes.I made my very aggro player +5 pops in season and he goes from averaging 3.9 fouls to 2.3.
Unfotunately I'm still convinced that a player having foul trouble will be always on trouble:
(40274448)Probably he could be worst than his actual average but...
One of the suggestion I proposed before having all the new bugs was to have a kind of specialist for fouls and potentials
1990-2022 Stalinorgel - https://www.youtube.com/watch?v=pV-Xppl6h8Et