For various reasons, I wanted to install Big Sur 11.7.3 on HFS+, but I could not do it. The install would always try to force-reformat my drive, so I eventually gave up and went with the APFS. Now I find out that an HFS+ volume can be installed as a separate volume on an APFS formatted drive. But could that HFS+ volume run Big Sur? Or are both these options a no-go? I haven't been able to find a specific answer to this. The target Mac is a 15" MacBook Pro Mid 2015 with a half-terrabyte SSD and 16GB ram. I know Carbon Copy Cloner won't do it, but is it even possible? At this point, my guess is "no", but I would sleep better, knowing. Thanks!