Welcome to the board
It's Robert Fripp playing the guitar part... at his wildest, so it's probably "Frippertonics"-ed out.
I've seen clips from that sing from various tours and every guitarist plays it differently... though I'm sure Adrian Belew did something similar to Fripp. On the '84 tour Carlos Alomar did the lead and just played a funky chorused part for the solos (Earl Slick seemed to be playing power chords).
Anyway, I've played a couple of Bowie tribute nights and have done this song, stomping on a distortion pedal for the whacked out parts and and playing clean chorused funky stuff... bouncing between the two.
High pitched jarring chord?
Just a Gm at the 15th fret, with the A# added on top
they slide that voicing down 2 frets to a Fm at the 13th fret, and that's that riff
Verses = Gm - F
Choruses = Bflat - Aflat
Bridge = Dm - C - Dm - F - C - F
There's a few little riffs I picked up from the record, but other than that I'd just improvised screaming licks with fuzz+delay+chorus.