I would (though you could finagle it with links and stuff), probably keep home discrete for each distro due to all the config settings stored in home.
I would make a separate agnostic data directory for large and common file storage.
I’ve tried to share home…but it’s just not a good idea unless you want to tinker with all kinds of links elsewhere (imo).
My opinion is that you shouldn’t use partitions at all. Well, it is my opinion so take it with a grain of salt
The idea is to create a single BTRFS partition and moving distros to different subvolumes.
I currently have only Windows and 1 Linux distro installed and managing even that is difficult for me, creating many partitions for many distros would inevitably result in lost disk space and complicated booting.
This is how I do it:
Install any Linux distro as normal. Choose your BTRFS volume as root and disable formatting
Boot from live media, from the live media
Move the subvolumes
Mount subvolumes and EFI partition
Add new installed bootloader to your current bootloader of choice. If you use GRUB, use the command configfile.
When I share these directories with multiple users (on a single distro), I always seem to have permission issues even when I change the permissions properly, creating a common group, adding all users to that group, and changing ownership of all files and folders to that group. I’ve even tried sticky bit permissions but even that didn’t help unless the permissions were very relaxed.
One user per DE . First user is KDE and 2nd is LXQt. It seems they don’t play nice together when used with the same user.
I reason I do this is because I don’t distrohop (like many people), but I DE hop.
I would like all users to have the same permissions for the common folders including Downloads, Documents etc. and certain folders which are synced from other folders using syncthing.