Lowering piston limit could be helpful. They might already have done that, decreasing the limit to 2k, but that is still a lot if connected to an ore gen.
I've noticed a few changes to the stacking over the last couple of days, that could also be a solution to some of the lag problems, if done properly. Since massive amounts of entities can cause a ton of pressure on the tps.
lower the amount of stacked entities that can be spawned loke drejzen said
Lower the amount of pistons allowed to be used on an island to 500-1k
Upgrade the RAM of the server so that it can run a bit more safely and functionally
Lower the amount of particles that are used in spawn. There are a lot of people in spawn and when i try to go to spawn, my fps drops to 0-1 especially when i look at the chests.
Close out islands when nobody on the island has been on it for 2-3 months
Use fewer NPCs at spawn
Delete some of the unusable plugins like feelings
Make it so ore gens or large redstone machines turn off after 10-15 minutes (make it so it counts the redstone in the 6 chunks around it. If theres more than a specific amount, it automatically shuts off after the amount of time)
Make it so cactus falling from large farms doesnt cause so much lag