My season 6 theory (Illusthrater spoiler)

So Marinette chose Alya as a new guardian in case something happens to her and everyone freak out. Like "Marinette will get badly hurt!" or "Marinette will die!!!!" or "We have seen her in the future and she seemed fine WTF" and let me tell you. She is gonna be fine.
What I think will happen: it will be a one episode thing. Marinette will get either amukatised or resign once again or just need a break. Alya will step in as Scarabella and temporary guardian. She will give Fox Miraculous to the newsest Mary Sue addition: Sublime. She will see for a day that being Guardian and leading team is stressfull and at the end everyhing will get back to normal.
Fans really like to exaggerate and freak out at the smallest occasions. But we all know how Miraculous world and plot is.... I would LOVE to be wrong but I strongly doubt I will