Does Overwhelming Splendor remove the activated abilities of planeswalkers controlled by the enchanted player's opponents?

Overwhelming Splendor enchants a player and has two main effects: it removes all abilities from creatures that player controls and makes those creatures lose all abilities and become 1/1s. The enchantment's text specifically targets creatures controlled by the enchanted player — it does not affect any permanents controlled by that player's opponents.

Planeswalkers controlled by opponents of the enchanted player are completely unaffected by Overwhelming Splendor. Their loyalty abilities remain fully functional and can be activated as normal. The enchantment creates no restriction on what opponents can do with their own permanents (CR 201.4 — an ability only affects what its text specifies).

Additionally, even if we considered the enchanted player's own planeswalkers, Overwhelming Splendor only strips abilities from creatures, not planeswalkers. Planeswalkers are a distinct card type (CR 306.1), so their loyalty abilities would not be removed even for the enchanted player's own planeswalkers.

Concrete example: Alice controls Overwhelming Splendor enchanting Bob. Bob's creatures lose their abilities and become 1/1s. Alice's own planeswalker, Chandra, Torch of Defiance, is controlled by Alice (an opponent of Bob), so all of Chandra's loyalty abilities remain completely intact and usable.