Are you implying that Mbappe will score goals into his own net? In order to please the management of Real Madrid even more

In fact, I do not think that in this match there will be at least some background to this transition (which can already be considered as 99% completed). All football players will try to show their best game and maybe Mbappe will be able to score, but whether this is will be enough for overall success is unknown (my prediction: not enough).
Actually I look at this issue from a totally different angle. If I was Mbappe I wouldn't want Real Madrid to win the Champions League the year before I sign a contract with them. In fact I would want them to lose early and then when I join the team win the trophy, so everybody says that Mbappe made the difference. I never thought a player who was about to transfer to another club would harm the club he is currently playing for.
To some extent you are right, but in this case the situation is a little different. PSG is just a bag of money, and Real is a legendary club that wins the Champions League regularly. No young name can change this balance, even if Haaland, Mbappe, Vinicius, etc. are included in one player. No one will say that one player made the difference.
It is naive to assume that Real will play defensively in this pair and will give PSG a lot of chances to score.
Why it is naive? It is my prediction, I consider how Real Madrid should deal with PSG strikers. I think Real Madrid coach may consider about this. Focusing in defending doesn't mean Real Madrid stop attacking and has no intention to control the match. What I mean, those defenders must be more discipline and more strict to keep PSG strikers. You are misunderstood, I never state that Real Madrid players to let PSG players be easier in attacking.
PSG is strong in names. But are names on the pitch that strong? Remind me of the game this season, when exactly did the strikers do something at the extra level and PSG beat a strong team?
By the way, maybe Mbappe's efforts alone may not be enough, but there are other good players in PSG whose efforts in total may be enough to win

All we can do is wait to find out later which team was stronger. I think it will be Real. I hope no force majeure like coronavirus and injuries of individual players will prevent us from enjoying this confrontation.