My 2c fwiw and reminder I only just recently managed a 53 flat.
Your gear changes seem a millisecond late, especially into T1, try doing the final change down a smidgen earlier.
You're braking hair and I mean a hair too late for the entry to the back straight.
Try BB2 plus 2 not 3, youre nearly swapping ends in the two bogey spots for the 911.
You're leaving a lot of time on the table exiting the 1st tunnel and especially the following left hander. The 911 will tuck its nose in, youre Braking too hard, sort of..... I sort of feather the break, trail brake I guess, watch my lap above, youre leaving half a second at that corner or close to it.
Rev it out too, sometimes you shift up a bit early of when u dont need to, all the power is at the top end. Wring its neck.
Overall though, youre consistent and smooth other than locking the rears a bit so you will find time for sure.
Now, educate me please, I use csa weak which is basically off, i see you do not use tc but youre csa is losing its mind violently flashing away, this has gotta be hurting you no? What does strong csa feel like with no tc? Have you considered turning it off and using tc1?