this is more or less my current workflow but i feel that is quite difficult to use/find photos in my android phone due to the lack of one android app.

rm -rf /var

I don't know what I was thinking on to type it 😅

AFAIK immich organize photos with albums not in folders. So, If i move from immich to another software (librephotos, photoprism...), the new software is aware of albums? I am worried on organizing my photos every time I change of photo management application.

I have a domain... but I think DynDNS is not always available for every domain or by every domain seller?

Yes, you explain better :-) The idea is that shell.nix is my development environment so I would like to use that shell.nix to interactive shells (nix-shell) and to run scripts (non-interactive use). I understand I could use a nix-shell shebang in every script, but that requires maintenance (when I modify the shell.nix file, modify the shellbang of all my scripts) and it is prune to errors (for example, modify the shell.nix and forget to modify the shebang of my scripts).

In my case, there is no IP change. However, the TTL of entries seems to be 60 seconds and when Cloudfare/Google asks for the new A record, it sometimes fails. I am getting this error message from Cloudfare when I try to solve host.sub-domain.duckdns.org

EDE: 22 (No Reachable Authority): (time limit exceeded)

Thanks for all your answers! I will check some of the alternatives to duckdns.