I found out a bit more after looking at the MicroOS documentation.
https://en.opensuse.org/SDB:BTRFS#Default_Subvolumes
I think it’s probably going to be preferable for me to proceed with mapping /home manually in /etc/fstab after all. I don’t see anything there that indicates that this will cause problems in future. Either that or just remove the /home line item in fstab and use a plain ol’ directory in /var and use /var/home as the default location for user homes. I’m not managing multiple users on this system, so it won’t be a problem.