Let me throw another completely unexpected result in the mix.
I've been doing plenty Fisherman races in between things to top up my credits for tuning etc. I'm not great at the circuit, use the pug and usually end between 3:23 and 3:26 finish times. Enough for 97K.
Today I installed GT7 on my old ps4 pro. It came with the anniversary edition and I was curious how it would run there. Loading times actually aren't as bad as I expected (at least not for the ranch) and it looks pretty good, just some noticeable pop up (trees) while racing.
The mystery, I'm doing the race in 3:17 on ps4 pro, over 6 seconds faster. It wasn't even a great run, just a run of the mill as I've been doing. To check if it wasn't a fluke, I back out to the world map, did another race against a different opponent, 3:17 again
I guess I'll do my credit grinding on ps4 pro
(It installed the game and let it do its thing to retrieve my save and everything. I assume the car is the same)
Edit: Sadly I'm not any faster in race C on ps4 pro
However the field is cleaner, less clumsy, and somehow I get 5 green bars on ps4 pro, while only ever getting 3 yellow bars like everyone else on ps5. Different group of people, different server, less lag. It looks the same, except lap one is a bit choppy from the back.
Edit: I went back to ps5 after doing a 3:14 lap on ps4 pro. Then did 3:17 on ps5. Whatever I picked up on the pro rubbed off, now I'm also faster on ps5
Btw, races on ps4 pro keep crashing, or rather not starting, leaving me in auto-drive for 10 laps... Twice in 5 races.