It sounds like you may have sent in your support request over the weekend, so hopefully the team has responded by now. They usually respond to everyone within 1-2 days. If you haven't gotten an answer, feel free to PM me your email address and I can check with the team.
I should also mention that we actually have several computers in our office that use Linux as the daily driver OS, and we haven't encountered any of the issues you're describing. I've also setup several completely fresh Linux OS installs in the last 2 months where S3D installed perfectly and ran as expected, no root required. If you're having persistent issues, it's very possible it's something unique about your setup that we haven't encountered here. It would help if you posted exact details about your environment and what specific problems you are having.