Withercrown

• WWizards of the Coast2021-02-05
  Official Ruling
  Any effects that modify the enchanted creature’s power without setting it to a specific value will apply after its base power is set, regardless of the order in which those effects were created. The same is true of counters that modify its power.
• WWizards of the Coast2021-02-05
  Official Ruling
  Withercrown overwrites all previous effects that set the enchanted creature’s power to specific a value. Other effects that set its base power to specific values that start to apply after Withercrown becomes attached to the creature will overwrite this effect.

Rulings via Scryfall