Bought mbappe at 1.3mil, he's 1.8 today. Why?

Saved up all my coins to finally get gold mbappe last week before black Friday. He was 1.38 mil, and today he's ~1.85 mil.

How? I thought gold cards depreciate over time because they're in packs = high supply. Is it cus his promo cards are in packs rn?

What's the play here? Should I sell him now, make the profit, buy him back in 1-2 weeks? Idk how the markets gonna be but he's so good I'm tempted to put some cosmetic Evo on him and just keep him.

P.s. this is unrelated but I packed tradeable thunderstruck xavi