I will get downvoted for this but a Synology Nas is simple and does 90% of what google will do. They also have their own DDNS or you can use whatever you like.
Downside is tou have to buy their hardware. Unless you do the Xpenology route.
I'm using Autosync on Android for backing up my stuff, but have no gallery service on my NAS yet. I'm thinking about Piwigo, can anyone share some thoughts on it?
Photostructure is a strong starter, but development is slow and it's still missing important features like sharing. Also, it's not ooen source.
Immich seems great but doesn't (yet) support digikam tags ( and since my 100,000 assets are tagged/organized via digikam, I don't want to move to immich yet and have to start over).
PhotoPrism seemed pretty good, though it also doesn't (yet) support digikam tags. Also, their self-hosted version doesn't have all the features of their paid versions.
If you need a UI to have albums and share them then yes, the previously mentioned Immich. I host it as well, and it is truly awesome.
One caveat though: it is still pretty early in development, there might be breaking changes. For example a few weeks ago you needed to update the docker compose file because they changed dependencies.
My need for online photo galleries is just to direct friends and family to see them, I don't store photos in the cloud.
I used to put up my photos on deviantart, I have had a gallery there for almost two decades, but lately dA has become very slow to navigate, so I built my own site, I didn't need much, an index page linking to HTML galleries I export from digiKam.
After a few weeks of learning, designing and testing HTML and CSS, I have a nice index page that is responsive and easy to update and customize (in limited capacity).
This runs on a normal webhost, and is lightning quick to navigate, the galleries support browsing with the arrow keys, and just works.
There are three annoying things about it though...
To update a gallery, I need to recreate it in digiKam and upload it manually to the host.
I can't include notes with the photos.
I have to edit a link in every gallery to make it be able to go back to the index page and not 404...