This is my first post.
My suggestion is making RetroArch/Lakka playlists and library compatible for multi system setups, where multiple clients can access the same game library from one central server. When updating metadata and playlists from one client, every other device should have the same uptodate data.
I am thinking of something similar, as you can see here for Kodi (but without the SQL):
I have 3 RA devices in different rooms. My PC and my RPi3 can both access the “games” network share hosted on my Synology Diskstation. They also get the thumbnails from there and the saves are stored on it.
But the playlist are not compatible because of the paths.
Since the ROM base folder is configured in the retroarch.cfg, RetroArch could write relative paths in the playlists and interpret the backward or forward slashes itself depending on the running system. Cores could be defined by their name without path and extension. If one system doesn’t have the core from the playlist, you could define a fallback core separated with a comma.
My third device is a NVIDIA Shield running Android TV (not rooted). This is the most complicated to keep in sync with the others. It can mount network shares, but not writable. So I use FolderSync with Tasker to sync my Saves. The task triggers every time when I start or quit the Retroarch app and it runs just a few seconds. It would be great to configure Samba shares inside of the RA gui to bypass the limitations of Android TV.
Many thanks for your great piece of software!