Can I use Origin Forme Palkia VSTAR's "Star Portal" Ability to retrieve Wash Energy or Rapid Strike Energy from the discard pile?
No, Star Portal can only get basic {W} Energy, but Wash Energy and Rapid Strike Energy do not count as {W} Energy in the discard pile (nor in the deck, etc.).
Source: Astral Radiance FAQ; TPCi Rules Team (2022-05-26)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH10_40
SWSH10_40