Maelstrom Wanderer

• WOTC Official Reminder Textofficial rules
  Cascade — When you cast this spell, exile cards from the top of your library until you exile a nonland card with a lesser mana value. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.

• WWizards of the Coast2020-11-10
  Official Ruling
  Each instance of cascade triggers and resolves separately. The spell you cast due to the first cascade ability will go on the stack on top of the second cascade ability. That spell will resolve before you exile cards for the second cascade ability.
• WWizards of the Coast2020-11-10
  Official Ruling
  Maelstrom Wanderer gives itself haste.
• WWizards of the Coast2020-11-10
  Official Ruling
  No matter what spell you cast with the first cascade trigger (or with any cascade triggers that result from casting that spell), the second cascade trigger will look for a spell with mana value less than Maelstrom Wanderer's mana value of 8.

Rulings via Scryfall