Q.Black spots started appearing on my succulents – Any suggestions about what it could be?
About 3 weeks ago, we started noticing my Echeveria ‘Dick’s Pink’ started getting a couple black spots on it. Then gradually it began getting more and more spots. We’ve always been cautious not to over water it so I don’t think it could be that. Then 2 weeks ago we bought a Cotyledon Hybrid ‘Ace of Spades’ and within a couple days, it begun getting the black spots. I don’t know if it’s a fungal thing or a bug problem, or what it could be. The spots are hard to the touch and cannot be wiped away. I’d appreciate any help I could get!
-The first 2 images are of the Echeveria and the following 3 images are of the Cotyledon.

A couple of the images looks like a case of Sooty Mold and it also may appear to be a fungus issue.
I would isolate the plant and began treating with Neem Oil.
Treat every 3 days for 2 weeks.
https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm