With this Minecraft plugin, you can add ranks to your server and make players gradually increase their rank
You can add ranks to server very simply.To the ranklar(ranks): section you add a rank name and then their Group name
then you can customize how much money,experience or optionally
Skyblock Island level(you can use only if you have ASkyblock installed in your server).
This plugin is not dedicated to Skyblock type servers so you can
use it in other server types, too.
After you add a new rank and save the config file in plugins/CRanks/ranklar.yml,
you should run /cranks yenile command.
Then rank will be loaded.

https://www.youtube.com/watch?v=Vv4wjsmniF4&t=4s
Here is a video about how the plugin works.(In Turkish)