Mbappe wasn’t bought but came free although he has a high wage but Madrid is a marketing club and I would say the business part of him coming was weighed more higher than that of him playing better football. Although it wasn’t that much of a necessary signing since Vinicius is also playing through that position. But regardless I don’t still think he is a flop or wouldn’t hit his mark in Real Madrid because they have had many players that came and were even booed by the fans but turned out to be the most loved, example is Benzema and Modric. Modric was voted the worst signing in Europe then and Benzema was booed by the fans both ended up winning the golden ball. Another clear example is Vinicius Jnr who even played as a right wing back under Zidane, today he is the fans favourite.
Mbappe can also be like those players you mentioned at Real Madrid when he has completely changed and adapted well enough in Madrid. Although for now Mbappe is still not developing much at Real Madrid because he is still a new player this season, but over time he can definitely change and become better like some other players in Madrid. Only for conditions like now, Real Madrid really needs players who are fitter and also have great potential in winning matches because now Madrid is being hit by more injuries to their players.
All eyes are on Mbappe after he officially joined Real Madrid, and it is natural that he has not been able to show his best game like now. However, this is not entirely his fault because he plays more in his new position which certainly affects his performance. It would be a different story if he was initially a player who was not much noticed, so when he could not show something good then it would be considered normal by many people. However, the label of a star player will also be a pressure for a player which means he must be ready to accept all the very harsh criticism.