If you are used to Postpaid convention and prefer Postpaid while keeping your spending low. Can port to CelcomDigi kuning first. Then go to a phone shop not official Celcom or Digi store and change to CelcomDigi Postpaid 30XV. It has 20GB and Unlimited call but sort of not being advertised publicly.

It worth less than the CelcomDigi Kuning RM25 plan but more convenient if you prefer Postpaid and easier to track your spending let's say for tax purposes