Debian only with ssh installation or with gnome GUI / Desktop-Environment?

I don’t have any document stuff on PC its just for photo video backup with immich. Audio and some homeassistant stuff.

OK I think family is not an option so maybe I will take something like koofr into account

Could I go with an external hard drive and make a backup there? I don’t think an offside backup is possible for now only a cloud service would be an option.