From the replay I think it's mostly just that you arn't using the full width of the track making the turns shaper than they need to be.
Also from you speeds on the straight I think you could get away with less downforce.
It might be better to practice on a quieter server. With fox at blackwood on a busy server there are usually cars everywhere. If you are constantly dodging stuff it's hard to work on you lap times.
Nice to see the Redline evo bloke prove once again that you shouldn't drive and admin at the same time.
According to lfsworld the average racer age is 26, that means full time jobs and other responsabilites eating into free time. With hundreads of car/track combos where do these people get the time to make setups?
Most of them don't, they get fast setups elsewhere either downloading or asking for them in race. Then if required they tweak them for their driving style.
While there are no statistics to prove anything I would bet the majority of races are driving with setups they didn't touch. Those that do touch them most will have made small tweaks to match their driving styles. Then there is a small number of people left that actually work on making the fast setups everybody else uses.
I have noticed one problem with BF1. In the pit lane with the speed limiter on turn off traction control and floor it, you will break the speed limit for a short moment. Looks like the car accellerates too fast for the limiter and has broken the limit before it has a chance to cut the throttle.