if u want to know the fastest line, get the wr replay.
after watching i saw that u take the turns to wide.
and of course that drift in T1 isnt helpfull
if u cant control the throttle as well as needed, just do it like i do (mouse driver) and drive the turn in a higher gear (ex. its a 2nd gear turn but u take it in the 3rd).
The reason that you're sliding in t1 is your downshift into 2nd and where it's placed. (That corner can be taken in 3rd in most setups I've tried anyway, same with the final chicane.) Besides that you really need to make everything a little more fluid, AKA what I'm seeing is brake, turn, accelerate, turn, accelerate, instead of one fluid mix of inputs throughout the corner. Another thing is when you're hitting curbs you want to be driving as straight as possible, this prevents the snap oversteer of riding up on the curb. I'm not saying that you should try to drive as straight into the curb as possible, but when you're actually riding over the curb the car's balance should be near neutral. Also on the final exit curb from the last chicane, you can eat as much of that curb as you want and just drive straight over it in this track/car combo. Finally, this would be the truly hard thing to do at this point, when exiting the high speed slalom you should be hugging the final apex and then go wide for the entrance to the chicane. I say this will be the hardest thing because you'll need to heavily manage your braking to make it into the entrance. What I do for that corner is aim for about the center of the track aiming for the outside curb when I start my braking, and then continue going towards that outside curb until I can turn right into the chicane, all this while under braking including the final turn in for the chicane. My PB on the track/car combo is 1:00.78 under race conditions with no draft, so I have a decent idea about the advice I'm giving.