The best method to prevent problems with events is simply to do exhaustive server-side checks, leaving nothing to chance, even a simple check of where the player is or a timeout between calls to the event can help. Remember that it is always the server has to decide whether to give an item etc.
The only thing that in my opinion makes sense for an anticheat is what already fivem server-side offers, which is the ability to block the propagation of spawned entities with mod menus or blacklisted vehicles/weapons.
If something is written in an unsafe way anticheat can’t do too much.
This is my opinion, do not take what i wrote as absolutely true, i also continue to learn (even though i have been part of this community for long), so if you have any constructive contrary opinions please write them