I'm not sure this counts as a single shot, but I've always felt that I could fix "Raya and the last dragon" with one flashback right after Sisu shows Raya her petrified brothers and sisters.
Context: Sisu's plans up until this point have always revolved around 'give the bad guy a present' which never works, while Raya is 'action girl' and all her plans are fighting or running. The last shard of the dragon crystal to 'save the world' is in the hands of 'evil girl' who caused the 'magic apocalypse'. After this scene, Sisu convinces Raya to go with the give 'evil girl' a gift plan, which get Sisu killed, then later after Raya and 'evil girl' fight, she does a 180 and gives up all the dragon shards to her and 'evil girl' saves the day. So the gift thing has no resolution, and the 180 is weird. How do you fix it?
Flashback: Sisu loves giving gifts to humans. One time she gives a gift and humans fight over it. This causes the evil greed clouds to attack for the first time. Other dragons make gem, entrust Sisu with it "because the one who caused it should be the one to fix it". Flashback over, Sisu says "and I will, even if I die trying." Bam, death foreshadowing, 'evil girl' saves the day foreshadowing, reason WHY Raya does a 180 at the end, and also lore on evil greed cloud things.