I’ve been watching the efforts of the American Chestnut Foundation for a long time. The link below suggests that the seedlings of the Darling58 tree might be generally available late next year
https://www.esf.edu/chestnut/progress-report/2021.htm
The darling58 is somewhat controversial. There are people like me that would like to plant a couple of trees. On the other side are some powerful environmental groups. They don’t have a problem with releasing the genetically modified American Chestnut. They do have a problem with the slippery slope. The big logging and paper companies are waiting in the wings with GMO trees that they want to plant. And there are others. There’s some sort of something attacking the worlds bananas and scientists are frantically working on a solution there.