So far we let the mods handle the chunk loading mechanism on all of our servers.
We ended up with multiple mechanism and huge differences from one pack to another.
Some need power or items to work.
Some will chunkload a 3x3 other will load bigger areas. Some will load when players are offline. Some will just stop working for no reason...
Another problem is that we had cases of illegal chunkloaders causing lag.
In recent modpacks chunkloaders are working when players are offline and causing unnecessary lag.
In order to harmonise our servers and reduce lag, we made out own chunkloading plugin.
You can find a guide on GitHub
If you bought a chunkloader before and do not see any available slots when typing /chunklist let us know on discord.