I don't know if it helps, but I found some Panel that adds privileges on the server, see if any is what you are looking for.
You can try to find something for the VIP Core: https://github.com/R1KO/VIP-Core
There is one that is completely Russian: https://gamecms.ru/
See if any of these can help you. I particularly recommend Tebex, a problem that needs another plugin so that it can send commands to add privileges, I believe.