Put the service behind a personal Tailscale tail net. Can still access from all of your devices and nobody else can push or pull.
Could crib notes from olden days and have a public/ subdirectory where files you drop in there are available read only to the public internet via separate endpoint.
Can also have a blind drop box that does the other direction (but does not allow the public to read).
That way you are read / write from all your devices, can publish to anyone, and can let anyone share things to you, you just don't facilitate anyone sharing to anyone.
Could crib notes from olden days and have a public/ subdirectory where files you drop in there are available read only to the public internet via separate endpoint.
Can also have a blind drop box that does the other direction (but does not allow the public to read).
That way you are read / write from all your devices, can publish to anyone, and can let anyone share things to you, you just don't facilitate anyone sharing to anyone.