I ended up on Piwigo. It’s pretty fully featured and allows you to set up access controls for groups. Also has client apps.

In about 2014 we flew through an airport where some of these “customs” types shows was being recorded. They had signs up everywhere (I think in multiple languages) saying “episodes of _____ are being recorded here. If you do not wish to be recorded please talk to the crew” (or something like that).

But who knows what they’ve filmed for their cut-away shots, from the far said of the arrivals hall.

I guess you should expect shots of you walking to be ok. But probably have the right to opt out of having your “case” filled.

These are fully stand alone. Downloadable. So not strictly hosted I guess?

Does it need to be “hosted”?

I like both these:

yEd (https://www.yworks.com/products/yed)

Dia Diagrams (http://dia-installer.de)

I think yEd had a free version but closed source.

You might find some starting points or even projects or terms to look for in this article:

https://arstechnica.com/information-technology/2023/03/you-can-now-run-a-gpt-3-level-ai-model-on-your-laptop-phone-and-raspberry-pi/ .