Apparently, once you sell in a non-Apple app store - you can't go back. Not just for the app in question; You, as a developer, can never sell in an Apple EU App Store ever again. Not even unrelated apps.
Still appealing?
"Developers who adopt the new business terms at any time will not be able to switch back to Apple’s existing business terms for their EU apps."
Still appealing?
"Developers who adopt the new business terms at any time will not be able to switch back to Apple’s existing business terms for their EU apps."
See "Why is Apple giving developers two options for business terms in the EU?" https://developer.apple.com/support/dma-and-apps-in-the-eu/#...