Can you soak the quilt in Dawn dishwashing liquid? Here's a link to one description of how to do it:
https://suzyquilts.com/fix-fabric-bleeds/
You can also use Synthrapol instead of Dawn.
What type of washing machine do you have? Domestic front loaders do not use enough water to dilute dye bleeds. You can save yourself some work next time by doing the first wash in a machine that uses a *lot* of water and for soap use Synthrapol or Dawn (in *very* small amounts to avoid too many suds). These soaps suspend loose dye particles in water so they can be rinsed away instead of settling into fabric. Color catchers are not nearly as useful for this.