Thank you @Kobe_W .
Unfortunately, I see that the balancer window should be used when:
particularly when your data set grows slowly and a migration can impact performance
In my case the data grows very quickly (~5K IOPS).
Also, seeing the following desclaimer:
The balancer window must be sufficient to complete the migration of all data inserted during the day.
And am not really sure what the length of the window should be in my case, or what should I do if I don’t find the right window.
Is there any other option we can use? or can we make it less impactful in general? (without a window)