I’m certainly not an expert but that is my understanding thus far. They have made it clear that they want new content that has never before been published in ebook format. So my understanding would be if you took it down, published as an ebook, then thought, “this was doing better as a serial,” you wouldn’t be able to go back.

Regarding your published works with Radish, it’s not clear to me yet if you can take something you wrote for Radish that has never been in ebook format and publish to Kindle Vella. I would lean toward “yes" at the moment, but I haven’t seen enough information around that.