You need to run forge universal.jar. You’re running the vanilla minecraft server jar. If the universal jar is not in the drop down, refresh page to see if it then loads. If it’s still not there then you have to find it and copy it up in this case there’s a file (run.sh or something) that has the user_args in the libraries folders some where. If you’re savvy and can read code my proposed fixes at the bottom of the Forge 1.18 thread could lead you to what you would need to do.
https://discourse.codeemo.com/t/minecraft-forge-1-18-1-no-targetable-jar/5200/18?u=elpres