How come a good mobile platform photo viewer for smb do not exist?

Basically people are using network photo storage nowadays to avoid expensive device storage, but the idea of storing my data on non-encrypted cloud is disturbing. So I did some research on privacy focused solutions. I think they can basically sort into 4 types.

|photo viewer|encrypted cloud|self-host|
|:-|:-|:-|
|local index|iCloud/ente|?|
|remote index|not considerable|Immich/nextcloud|

As you can see there's something missing. Why are there basically no option for mobile platform photo viewer for smb? For years people are focusing on docker based photo libraries like immich. With local thumbnail and metadata cache and indexing it will run as good as the server option. Maybe lacking advanced features like object recognize but I don't really think I need that. It's not impossible because Microsoft Photos on Windows is doing exactly what I'm talking about only it's not on mobile platform.

https://redd.it/1x75jzv
@r_SelfHosted