There are a few things that seem a little out of tune to me, why do you have to make others threaten him to say things, even if it's joking, why make the mc so beta? If you don't want to say something, don't say it, honestly friendships delay more than they enrich, for example, almost 100% sure that you will nerf the mc on certain occasions to show "the importance of others" when fighting or solving a problem , just look how you mention the "talents" of others, I understand that you want to give him a strong partner in his adventure to accompany him, but let's be honest, nobody reaches the level of someone reincarnated and motivated knowing what is coming, it is not It is necessary that they accompany you in strength, there is more than power in life, you just have to be there and now.
I'm bothering to write this because I feel that it has a lot of potential, I don't want it to be ruined by signs of "low self-esteem" or giving away knowledge of power to others, my friend, individuality exists.
As for the couple, Fleur is honestly my favourite, her character faces many facets of individuality, pride, loneliness, excessive affection due to that, support and going to the end, I hope you portray her well, not like a teenager blushed by others or shy, it's okay for her partner, because normally only your partner shows your "weak" sides.
That being said, I like your fic, I would like to help you review logic and reasoning, for free of course.
