Get it into appropriate soil. Unfortunately, "succulent soil" sold out of a bag is actually almost invariably inappropriate for most succulents. They want freely draining substrate with just a small amount of organic matter. So a mix of 70% pumice, lava rock, perlite, chicken grit, fine penbles, etc and 30% organic soil (peat, coco coir, gardening soil).
Echeverias are VERY light hungry. If possible, gradually accumulate it to direct (outside in full sun) or strong indirect (in front of a south facing window) light. And I do mean gradually, giving slightly more light a day over a several week period, as plants can sunburn and it is generally permanent or fatal.
Echis hate having wet feet and only need watering every couple of weeks, but this one looks like it could use a good drink.
Good for you for rescuing it. Several of my favorite plants have a similar backstory.