Repairing my cactus and succulent garden

Since I have been focusing mainly on remodeling my store, I have had to neglect my plants a little. My daily visits became weekly visits.  This week, I started visiting my plants again and am trying to reorganize the nursery. The plants most affected by my absence are the cacti and succulents.  So I have begun the arduous task of taking them one by one and starting to separate them, checking for pests, changing their substrate, and transplanting them. I started with this crassula: it is the mossy crassula, also called St. Joseph's cord. It had grown very large in two pots, becoming very elongated in the shade. Now I have more plants and will place them where they will get a little more sun.  The Sedum adolphi had grown out of its pot and had not received much water in weeks, and the substrate no longer had any nutrients. I have separated it into several plants. Once they are well established in their new space, they will be put back on sale, with a new pot and well-proportioned substrate.  Echeveria pallida is one of the succulents that became infested with pests. It is a white, sticky substance on the roots and stem, which gradually colonizes it until it destroys it. By the way, I found it. I cut the stem near the roots, and now there are several plants.   Mammillaria elongata grows a lot, but it has also suffered. Two of mother elongata plants dried out from the bottom. The water did not penetrate their roots because they were too crowded in their small pot. I have lost several plants, and that saddens me.  Although I try to check my plants quickly and frequently, when I stack them, it is difficult for me to detect which ones are suffering. The Mammillaria prolifera was so crowded in its pot that the water did not reach its roots. I have four mother plants that have dried out from the bottom. Neither rain nor watering penetrated their stems and roots; it's very sad. When I started to remove them from the pot, I noticed that even though they still have flowers, several of them have dried out at the roots.  Some others I have only changed the pot and substrate, like this Morganiana; now I have two of them. This one also did not branch out due to a lack of water.  These are some of the cacti and succulents that I was able to save yesterday. I will continue to restore the others little by little. The harsh sun, the lack of constant rain, and my lack of proper care have caused my plants to suffer today. Soon they will all be changed again.  I took the photographs at night with the Redmi note 9. I think my eyesight at night is not very good. The photos are not at all of good quality. My phone is already crying out for renewal.