Personally, I would place Shang-Chi right before WandaVision, since it accomplishes everything you said it does, but it’s stinger also helps better frame some character continuity that starts in WandaVision & continues into The Marvels.
As for Quantumania, without getting into spoilers, you definitely want to put it before Loki Season 2. With Daredevil, Forbidden Marvels has a solid fanedit that cuts through the chaff of Season 1 of the show.