The only making-of I’ve seen that is just about as weird and disjointed as the film (and director) it’s about.

Ciao, Federico! (1970) - The Making of ‘Fellini Satyricon’
https://www.youtube.com/watch?v=sGxHCB1KBMo - from the Cinematographers on cinematography YouTube channel (1 hour long).

The blurb:
“This documentary film was produced by Gideon Bachmann in 1970. It features various clips from archival interviews with the legendary Italian director as well as plenty of archival footage from the shooting of Fellini Satyricon.”