A "market analyst" should know this, but there are a number of alternatives to this being an "exclusivity lump sum" that are a lot more realistic.
Most likely this is a milestone payment that will be shortened against future sales (or preorders existing at that time). Obviously Epic is giving something for the exclusivity, but 10M EUR makes little sense. Prepayment for sales, a guaranteed minimum number of copies sold and preferential treatment for a while is much more likely than a huge lump sum.
I'm not saying Epic couldn't afford it, but it just makes zero sense.
Btw, this isn't just me guessing, it has been reported before that Epic has guaranteed sales numbers in return for exclusivity (for ooblets and phoenix point).
This concept makes more sense for Epic, because if they can help the game succeed they end up not actually paying that much for the exclusivity. It also makes sense for the developer since they also have incentive to make the game succeed, which a lump sum payment would not really contribute to even if it pays the bills.