net/minecraft/world/entity/player/EntityHuman has an exp-cooldown field (in 1.19.3 it's called bZ). Setting this field to a very high value (Integer.MAX_VALUE) allows a plugin to prevent a player from being able to pick up experience orbs and also prevents the animation of the orbs moving towards the player. Currently this has to be done via reflections as there is no getter/setter for this field. Therefore I'd suggest adding methods like Player#getExpCooldown & Player#setExpCooldown that return/set the value of the exp-cooldown field.