I'm a little confused by the Mary Sue anon before. While I personally object to the "world only exists around Marinette" thing, because, like, she barely interacts with Gabriel who is the main villain, and we see things happening outside of her world view, albeit more in season 1, I will admit that all that is very subjective.
What I will object to is the "Marinette's jealousy led to outing Fu's ID" point, as well as the point that the show swept away the consequences of Miracle Queen.
Marinette did not give away Fu's ID; that was his girlfriend (Marianne I think her name was?) in Backwarder. And while you could argue the misunderstanding leading to that situation was caused by jealousy (Marinette wrote a confession letter to Adrien and it, alongside the letter to Marianne and the prescription all got swapped around), I would argue that if Marianne had read Fu's overdramatic letter, she would have had the same reaction, considering Fu was acting like he was dying.
If the Anon is referring to Miracle Queen, I will admit that my info is second hand since I stopped watching the show at that time, but I was under the impression that Marinette leading Love Eater or whatever that akuma was called to Fu, was because she got distracted from seeing Adrien and Kagami together, leading to her not detransforming before seeing Fu; you could easily argue that if she hadn't gotten distracted and did detransform, Gabriel would have figured out her identity.
And we're meant to believe that Marinette picking the Dragon miraculous in order to get Kagami away from Adrien was the wrong call, because she should have used the Bee, but at this point in the series, Marinette has already decided that Chloe is not getting the bee miraculous anymore, so if she had picked the bee, Chloe would have just gotten even more upset that Ladybug had replaced her.
Finally I want to touch on the last point, that the consequences of these mistakes were swept under the rug by the show (Chloe being retconned as having always been evil, Fu preferring his life as an amnesiac), but that's ignoring the consequences that arguably affect Marinette the most; due to Fu giving up guardianship, Marinette became a guardian before her training was complete. She lost the one adult ally she had as a superhero and had even more responsibility and weight placed on her shoulders. Fu's replacement in the form of Su-han does nothing to train her, and is more of a hindrance than a help (does he ever teach her the technique he used to avoid akumatization?), and then you have the fact that Gabriel got the translated grimoire, allowing him to use the Peacock miraculous without consequences and even combine it with the Butterfly.
Gabriel having the translated grimoire also allowed him to almost immediately circumvent Marinette's Lucky Charms with the Megakumas. And let's not forget that Marinette also lost any remaining privacy, now having to babysit the other kwamis who start causing trouble for her in the very first episode and refuse to listen to her, and that Marinette being guardian is what allowed Felix's miraculous stealing plan to work, thus resulting in Season 4 ending with Gabriel having all the miraculous.