Fati's buy out clause is exceptional, probably due to the labels placed on him when he first broke through. I would suggest in the current market your valuation is a little on the light side, 22 goals in 80 appearances for Barca might back that up.
Seem to remember Neymar had a buy out clause...
So how much do you think Fati is worth? He's not worth a billion but he's not worth as little as €200k. He's still not a home grown player from Brighton's perspective.