I haven't been able to improve the situation. I believe I might have made in how I move files prior to creating zfs pool and that might have screwed some configuration, I say this because when i access folders in regular Unraid Array it is fast enough, but not the same when accessing folders/files on zfs pool.
I don't recall exactly what I did so I can't fix it, I might end up resetting the whole server and starting from scratch.
Any recommendation on this last idea is appreciated.