I've been playing UT mode since Fifa16, for the last 3 years I've been getting constant packet loss, jitter warnings. Oddly enough the only game I've had this problem with is the FC series and I've done everything there is to do.
I had the main port checked, changed my modem countless times, redirected my ports, had the cable of my service changed to CAT5 cable, I've had a wired connection for at least 6 years, and I tried playing on different devices, but none of them gave me a solution.
My game has button delay, sometimes it doesn't reflect in the game even though I press certain buttons and this happens most of the time when I do skill moves, my player switches with the right analog do not work correctly, my game is always heavy as other friends have said and it is obvious that we are not playing the same game as my opponents.
Gameplay-wise, my opponents may be better than me, but I was a Div1 player before Elite Division was added, and I've played Elite Division countless times since then, and you can be sure that there is a huge difference between me in matches where I have connectivity problems and me when the game is smooth.
This lag makes me feel like I have to manually control all 11 players, during co-op rivals I've heard my friends say “man why isn't our team moving, it's like they're not taking positions” and when I played rivals myself I realized that this happens all the time and I always have to give my players an extra directive.
It was as if there was a problem in the optimization between me and the opponent and my game was lagging, and sometimes my game would freeze for a moment.
The FC 25 issue is very strange, as other players above said, there is a big difference between kick off mode and rivals in fut mode and even in squad battles, on the online side, command inputs seem to go meaninglessly late and the game feels like it is played at 0.75x speed.
Maybe it has something to do with the matchmaking system, and it's not routing correctly, but it's very annoying, and I can tell you from my years of FC experience that this company doesn't care about this kind of problem for its players.