This plugin will allow you to limit the use of gems during combat.

Depend: CombatLogX, PlaceholderAPI

Configuration:
# Cooldown settings (in milliseconds)
cooldowns:
pearl: 5000 # Cooldown for ender pearl usage
message: 1500 # Cooldown for action bar messages
messages:
no-placeholderapi: "&cPlaceholderAPI not found!"
no-combatlogx: "&cCombatLogX not found!"
plugin-enabled: "&aPearlCooldownPlugin successfully enabled!"
pearl-cooldown: "&cCannot use ender pearl! Wait {time} sec."