Not a succulent expert by any means, but the fact that it's growing some air roots and the dropped leaves also are trying to root also seems to point to not enough water.
We have a big jade that will air root when it's too dry. Before it gets to that point it's leaves will look noticeably less plump.
Succulents do require watering, but it's very important to not overdo it. Our Jade is probably only watered ever two months or so when it's outside (on an east facing porch in zone 6) during the summer and even less frequently in the winter. I know it well enough to be able to eyeball the plant at this point.
I have a graptoveria that produces air roots constantly, mostly because despite having a perfectly good pot and light source, it does its utmost to grow outside of the pot. Every year I have to chop and prop it to save it from itself.
Some succulents grow in such... seemingly unsustainable ways for the mother plant. I guess ultimately these are all some kind of propagation strategy for the plant though.
Alloe will overground their pots with tons of babies and fall over when they get too big.
Our big jade will intentionally dry out the center of some of its smaller branches to make the ends of the branch fall off in hopes of rooting.
I guess this is why the plants have been successful. It does make for some level of struggle as a house plant though, lol.
Can you grow a new plant off just a leaf or would it be like normal plants and just keep the leaf alive if there's not some "branch" with it to establish a clone?