I am trying to get all products based on catalog price rules and cart price rules under all categories which is valid for today's date in Magento 2
For catalog rule, if you look at
You will find method
getMatchingProductIds() which return an array of all matching products for a particular rule.
So load the
rule Model by using
rule id by object manager or constructor injection and call
getMatchingProductIds() method. Hope it works.