Welcome to PhotoStructure, @jcfrosty !
Convincing family members to change anything is tough: the best you can do is fetch Google Takeouts so if they have their account closed, the damage is minimized.
Here’s a list of the features I saw you ask for:
multiple users support
This is what this forum post is tracking. Note that this is currently supported by just running multiple instances of PhotoStructure pointed to different library directories. If you use docker-compose it’s quite straightforward: set up each person with their own library and their own port number, and their own “website” will be completely separate from each other. I’ll be building simpler user auth before this feature is tackled, which just has 1 or more “owners” (via username/password/TOTP) and optional “viewers” (via username/password or token).
login, 2FA
I’ve referenced this as “user auth” here and on Discord, and will be built as a prerequisite to this multi-user feature. I’m interested in building out multi-device FIDO support, but that’s a year out before wide support is available, I think.
album/photo sharing
This is also coming after user auth. Vote for it here–feel free to add ideas/feedback as well.
I’m also looking for how to automatically backup images and video from iPhone.
There are a couple solutions external to PhotoStructure that do this well, so I’m not adding this functionality at this time. See this post for details.