On Prime, the Harry Nilsson documentary was interesting.
"The Making of "Wildflowers" is great as well
Movies about music, based on music, videos of the artists or even filmed musicals.
My favorite 80s era of music got me into various artists from MTV and certainly I was interested not only to listen, but also to see my favorite artists
Overall favorite music movie I'd choose TWO MOON JULY with line up of David Byrne, Lori Anderson, Adrian Belew, Arto Lindsay and William Burroughs. That is definitely one of the best combination of artists of predominately NYC underground. I first saw that on one-sided laserdisc which should be around 40ish min long and I liked sound and video.
https://youtu.be/_W7B_n0oiUI?si=I29ThFCftF5BlBcx
Early videos of Mylene Farmer are nearly all made just as movies
https://youtu.be/ZfmC9Hj73C0?si=l1QDxvMIxv7KEpMW
Also as musical I'd choose second version of Mel Brook's "Producers"