I'm transitioning from Apple Photos to Immich. One feature I use in the Mac version of Photos is its support for multiple photo libraries. One library holds iCloud/phone photos; another holds game captures; another holds saved artwork, etc.
The key thing is that these libraries are strictly separate. Nothing is shared between them, but I can freely choose which one to view. When I alt-click Photos, it lets me choose which library I want to load.
Is there a way to replicate this functionality in Immich? Right now, I've successfully mirrored my main iCloud library. I'm looking to create an entirely separate library for my game captures that doesn't mix with the main library at all, but that can still be accessed easily.
(Immich's support for "external libraries" is not what I want here. If I understand right, it pulls in assets from other locations and displays them in the main timeline.)