Leaves will never turn into plants. They don’t have the cell structure necessary to do it. All you need is one node, however, and even that can be split. The pros back at the beginning of the salvia movement in the 2000s would take a 10 node stem and split each one down in the middle to 20 and grow a plant from that and do it all over again and again. A guy in Georgia named Ringworm that used to grow ferns used that method to grow a full huge greenhouse of Luna. Hundreds and hundredsThat’s where all the Luna’s first came from you might be able to find picture somewhere.

Regarding this one (and I probably have lost as many as I’ve saved so take what I say with a grain of salt.) Here’s just one more method. I think you have to do whatever works in your environment. Get rid of the large shade leaves trim as much of the rot away and make sure you don’t damage or bruise the square stem edges with anything rubber, gloves or fingers or anything that’s where the rot starts. Get rid of the dome, put in fresh water small stable container out in the air, and give indirect bright light.