Running a Spark profile for lagging tics on my server, I've found that the function net.minecraft.world.level.pathfinder.SwimNodeEvaluator.getBlockPathType() from the cachalot whale AI is taking up a majority of processing time.
We have a house near the ocean and there are frequently up to 4 whales nearby, here's the profiler log: https://spark.lucko.me/wn9EIfr8IZ

How many ticks behind is your server most of the time?
Mine tends to be 40 - 70 ticks behind, I wonder if its this.

Edit: ahh I see your profiler says ticks >= 150
Might have to setup something like this myself, the mod breakdown is cool.