Thanks for posting. To clarify, are you running the benchmark using the command `./geekbench4' in Terminal? If so, are you seeing any output afterwards?
If you input ./geekbench4 --help you should see a help menu afterwards. To enter your license key, input ./geekbench4 --unlock <email> <license key> (substituting your email address for and your license key for )
Instead of accessing a Tools menu to export your license (as stated in the knowledge base articles), because the Linux version is run using the command line, you will need to use the command --export-license <directory> entering the directory you would like to export the .preferences file to. Let me know if you need anything clarified!