Okay this has been bothering me since launch, and I don't see PD fixing it because it's heavily dependent on which gen console the players in the lobby are playing on. I've found through my own testing, and through those of my friends', that if you have a lobby - public or private, doesn't matter - with only PS4 players, or with only PS5 players, the lag drops significantly, and the game is really smooth. For us drifters, that's great, because we can get in close proximity to our tandem partners without fear of them rubber banding or jittering too much. The instant you add more than one player on a different gen console, the lag returns, and you get rubber banding, larger hit boxes, jittering, etc.
On top of that, the pit entry/exit lag that's been around since 🤬 GT6, becomes worse when you have two different gen consoles in a lobby. In GT6 and GTSport it presented as a slight stutter. In GT7 the pit entry/exit lag freezes the entire lobby for what feels like half a second (I don't have concrete evidence for this, I don't have the equipment to measure it, so take it with a grain of salt). That freeze not only removes input from a controller, but also a steering wheel.
So imagine how frustrating, and also dangerous for those of us on direct drive, to have your steering input go limp mid tandem. Try catching your car during one of these moments. Your best bet is to hope it happens on a straight or during a long slide; not in between transitions. So far, the only "fix", is to hope you have players that know of these issues and have proper lobby etiquette, i.e., enter only when a tandem train finishes its run.
I'm tired of the excuses from PD, I'm especially tired of the fans that enable their behavior by making excuses on their behalf, and I'm tired of being told to get over it. You would think after so many years in development, with GTSport's engine being the test mule, that they would have ironed these bugs out by now. Instead they get worse with each game release.
This just further solidifies what I've been saying from day one; making this game cross-gen is a mistake. I got crucified by my friends for even mentioning that, especially during the first year of the pandemic when no one could even get their hands on a PS5 - that is still the case, unfortunately - however, it's true. This game is not optimized with the PS4 in mind. If it is, it's not optimized to share server resources with the PS5. For some bizarre reason, they've made track props client-side, but inputs server side.
GTSport was already pushing the PS4's architecture to its limit, GT7 damn near breaks it.
For the first time in my "gaming experience", I will actually advocate in splitting the community. Give us the option to turn off cross-gen, because having to run two different versions of the game on the same server is not working out.