Adding to MongoDB a new shard. How to minimize Impact on server loads

Question

Is the possible to minimize Impact on server loads while adding to MongoDB 4.2 a new shard?

I have found this recommendation. It could help but I sure should be few more thing which we can do.

Prior to a new shard, I would first explore setting your read preference to SecondaryPreferred. This will allow your primary node in each RS to leverage more resources for Write operations. (c) lost

Thanks