FYI there is a OSRS themed minecraft server with skills and everything : r/2007scape
10 Best Minecraft Servers for Kids and Why
SKILL GUI (with few basic variants) - MCModels
Skills Pro | SpigotMC - High Performance Minecraft
My RPG Skills Datapack is now Re-Scalable...in other words, you can set your own custom base xp requirement and change it at any time without xp loss for players. Excited to see
FreeRPG [1.15-1.16.5] | SpigotMC - High Performance Minecraft