Here's a video essay that explains the narrative device known as deus ex machina, how to spot it, its strengths, and its weaknesses.
Deus (2022) (Film) - TV Tropes
Deus ex Machina by K. Alexander
What is a Trope — Definition and Examples in Movies
10 Worst Cases Of Deus Ex Machina That Ruined The Anime
What is Deus Ex Machina — The God From the Machine Plot Device Explained
Deus Ex Machina (1984) (Video Game) - TV Tropes
Deus ex Machina (2007) (Web Animation) - TV Tropes
What is Deus Ex Machina? Definition & Examples - The Art of Narrative
Deus ex Machina (2008) (Manga) - TV Tropes
Lion Turtle (To the people who think he's Deus ex Machina) : r/TheLastAirbender