Fuss // Bother

• WOTC Official Reminder Textofficial rules
  Surveil — Look at the top N cards of your library. Put any number of them into your graveyard and the rest on top of your library in any order.

• WWizards of the Coast2024-02-02
  Official Ruling
  Split cards have two card faces on a single card. The characteristics of the half you didn't cast are ignored while the spell is on the stack.
• WWizards of the Coast2024-02-02
  Official Ruling
  A split card's characteristics are a combination of its two halves while it is not on the stack. For example, Cease // Desist has a mana value of 8 while it is in your library. If an effect allows you to search your library for a card with mana value 4 or less, you can't find Cease // Desist.
• WWizards of the Coast2024-02-02
  Official Ruling
  To cast a split card, choose one of its halves to cast. There's no way to cast both halves of any of the split cards featured in this set.
• WWizards of the Coast2024-02-02
  Official Ruling
  Each split card has two names. If an effect instructs you to choose a card name, you may choose one of those names, but not both.
• WWizards of the Coast2024-02-02
  Official Ruling
  If an effect allows you to cast a spell with certain characteristics, consider only the characteristics of the half you're casting. For example, if an effect allows you to cast an instant or sorcery spell with mana value 2 or less from among cards in your graveyard, you could cast Cease this way, but not Desist.
• WWizards of the Coast2024-02-02
  Official Ruling
  Each split card is a single card. For example, if you discard a split card, you've discarded one card, not two. If an effect counts the number of instant and sorcery cards in your graveyard, Cease // Desist counts once, not twice.

Rulings via Scryfall