Since Whatbox allows you to SSH into your seedbox, you can setup slskd manually (root not required) and access its WebUI remotely.

Just letting you know, don’t use the docker container (it’s podman for whatbox but I digress) as you won’t be able to correctly forward the ports. I tried setting it up this way and worked with their support team and they said it wouldn’t be possible because of how they allocate ports.

I’m not familiar with that seedbox provider, but unless you have a virtual private or dedicated server then you’re limited to the applications the host has made available.

If you do have a private node with root access, then you’ll be able to install whatever you like. Generally, these are limited to a command-line interface, in which case you’ll need something like soulseek-cli, but higher-tier hosting packages often support remote desktop which would allow you to log in and install the graphical version of the app as normal.

“I rent seedbox at whatbox and want to share it’s content over people from soulseek”

I just can’t believe that’s a sentence.