Help regarding setting up Firebase Rules

Reading what conditions I am writing will need a bit patience, I thank you for this.
Here is what I want:-

I want all project buckets should have read permission to be true and write permission to be false except:-

All $uid buckets should have read to be true and write to be $uid === auth.uid except three buckets named BUCKET1, BUCKET2 and BUCKET3 should have read to be true and write to be auth != null.

Thank you for reading this.

Can you help me setting up the rules for making this possible?