Linux can be a little tricky to navigate at times, especially when trying to set up game servers. Have you tried launching the server directly from SteamCMD? That's usually the easiest route to take. As for your issue with the third-party mod, I've had similar problems in the past. It can be frustrating when guides assume you're using something that you're not. Have you tried reaching out to the community for help? There are some great forums out there where you can get advice from fellow gamers who have been in your shoes. Regarding
7 days to die servers , I've found some great ones to play on by doing a little research online.