Answer to the question, “Is rūpakkhandha synonymous to nāmarūpa?” is no.
It will become clear in the upcoming posts. But the following is a quick answer.
Rupakkhandha of “old memories” can back to the mind when one just tries to remember that memory. For example, one can recall what one ate for lunch yesterday.
– That does not involve Paticca Samuppada steps, “avijja paccaya sankhara, sankhara paccaya vinnana, vinnana paccaya namarupa.”
We will discuss the mechanism for recalling past memories in the upcoming posts.
– It is essentially, “mananca paticca dhammeca uppaddati mano vinnanam.”
– But that requires more explanation.