

If you are already hosting Nextcloud, the Memories app might fit your needs well.
Immich definitely isn’t a bad option either. It doesn’t take ton of resources, has a clean user interface and is multiplatform. Just like Coolie4 said, you can just try it out with a small collection first before committing to anything.
If you don’t want them on cloud providers because you’re not comfortable them being able to see those pictures, you can also pay for Ente.
Self hosting Ente is also an option, which is what I use for my family
You might also be able to get away with hosting something like Seafile and use directories as albums. But you won’t get random shuffling in that case (My bad I can’t read. This isn’t much better than what you’re doing currently)
Maybe you can use some client to navigate your share in a more pleasant way instead of hosting something new? I never tried that so I can’t recommend anything for that unfortunately