What's your question? Ask

This is Crassula perforata, String of Buttons.

https://www.gardeningknowhow.com/ornamental/cacti-succulents/crassula/string-of-buttons-crassula.htm

We don't make vendor recommendations, but Kebab bush (Crassula rupestris) is offered on many succulent sites. You can peruse those online to look for new varieties.

You may have some root rot going on. I would repot it in a sanitized container with fresh potting soil for cacti and succulents. Make sure the pot has drainage holes. This one may not. It doesn't really help to put rocks in bottom of container.

I would also cut off a piece or two of healthy foliage and try rooting it in case the repotting doesn't help. Here is more:

https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/how-to-stop-succulent-rot.htm

It could be too much water or humidity. Follow these instructions when propagating your succulent plants.

https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/propagating-cacti-and-succulents.htm

It could be the shells of scale insects. There still could be hard-to-see juveniles or eggs on board so I would treat the plant for scale. Here is how:

https://www.gardeningknowhow.com/houseplants/jade-plant/pests-of-jade-plants.htm