I promise, your backstory is probably fascinating! But it is not reasonable to ask your reader to sit there and let you explain it to them before it’s relevant to any characters or plot elements that they care about. Blaming the reader for impatience isn’t practical. It’s not their job to humor you, and you shouldn’t want to be humored. You’re writing this story for them, to bring them into a world you made and to make them care about the people in your world. Don’t reject feedback like “You infodumped and I zoned out.” It’s not that your information isn’t important. It’s that the way you’re giving it to us is inaccessible.
Once people care about your characters and world, then you can sell prequels to fill out the backstory. Not only is infodump bad fiction writing, it is bad business.