[digiKam-users] Multi-user digiKam setup?

[Leo Gaspard]

Hello world!

I have tried IRC to bother the fewest possible people, but it looks like
#digikam at irc.freenode.net is dead, so let's try here. Sorry for the
noise! (Note: I am not subscribed to the list, can you please keep me in
the Cc: list?)

I am considering using digiKam, but as my use case is kind of peculiar,
I thought I would first ask whether you think I have chances of
succeeding at what I'm trying to do.

Context: I'm trying to setup a shared photo database with my family for
all our photographs. Photos will be shared over NextCloud, and hopefully
digiKam would be used to both tag them and synchronize the tags. Now,
the photo database is kind of huge, and not all computers are able to
download it in full. In addition, not everyone has the same taste for
photos, so I think it'd be better if everyone only had write access to
their own directory, and read access to others'.

My currently imagined solution:
 * Each user puts their pictures in their write-for-them read-for-all
   folder in Nextcloud
 * Everyone runs a digiKam instances. Tags are synchronized either
   through MySQL or by just adding the SQLite database to the Nextcloud
 * digiKam is setup to directly fetch the photos from WebDAV from the
   Nextcloud instance

So my questions are:
 1. Do you have advice on whether to pick MySQL or synchronize the
    SQLite database over Nextcloud? (I will have linux, windows and mac
    clients)
 2. Does digiKam handle well-enough collections on read-only folders?
 3. What do you think about the overall idea?
 4. Bonus question: Ideally users could also have their own private
    databases that are not shared. Does digiKam handles properly
    switching between two databases, ideally  with one that includes the
    other?
 5. Trick question: If an answer is no, is there any project other than
    digiKam that could handle these requirements and that you would know
    about?

I've searched a bit the manual and didn't find much about these
questions, and I must say I'd rather request an opinion from someone
knowledgeable before starting the setup, that will likely be kind of
long and complex, especially if done with MySQL. Sorry if the questions
are already answered someplace I didn't find!

Cheers, and thank you for digiKam that looks like some nice piece of
software!
  Leo