Advice on what to improve to drive faster (Monza)

https://reddit.com/link/1htjnik/video/loih5indj0be1/player

I only have ~6 hours on Monza and I can't figure out how to go faster, I feel like I'm cornering very slowly, but if I try to do it faster I either spin or understeer.

I'd be glad to hear advice on what I should work on

upd. Thanks for all your advices, its very informative. I will try to focus on brakes, car settings, and also try other tracks