I followed up on github as you suggested and a very nice young man took a look at it and said that the code already does work the right way (at least the way I and their little poll think it should work). But, it turns out that the fix (from 2021) has not been deployed - it's to be in the next release.
So I don't know what will happen now - I'll continue to use my workaround, so I'm happy enough.
Another approach entirely is to use pam_mount(8) which can automatically mount a disc on login. I use it to mount /home/$USER (obviously this couldn't be used to mount the root fs !!)
You can't avoid IBM/RedHat - they contribute to the kernel and many, many other parts of Linux eg systemd. I have no idea what you mean by DIY distros, what a peculiar adjective in this context. Linux itself is DIY. Life is DIY.
That said, voidlinux is an independent distro without systemd or snaps based on runit for init and xbps for package management. It's also a STABLE rolling release.
I followed up on github as you suggested and a very nice young man took a look at it and said that the code already does work the right way (at least the way I and their little poll think it should work). But, it turns out that the fix (from 2021) has not been deployed - it's to be in the next release.
So I don't know what will happen now - I'll continue to use my workaround, so I'm happy enough.