I have a sequoia iso I made from the apple servers.
I’d recommend you use OSX-KVM and download the baseimage file and dmg2img it and then add it to the VM as a raw file.
I have a macOS.dmg I converted from dmg to cdr then to iso. I will give that a shot.
I would recommend you go from dmg directly to img.
I used the Linux tool you recommended and did the dmg2img, and I saw the MAC base system come up at the open-core bootloader.
I have been trying to boot it for about an hour, and nothing has happened; it is stuck on the Apple logo.
I know that for me, I had to boot it like 3 times and wait about 30 minutes at the Apple logo. The first 2 or so times it would go for a while then hang but then that would make progress for the last time that worked. Also, do not shut it down as soon as it freezes because it actually keeps working for a little while after the screen and mouse freeze before it eventually hangs entirely.
I got it running. I think it was a misuse of the VirtualCPU I had it set to 1, changed it to 4 and the VM Booted.