@OrangeDragon
Which kind of succulent have you tried, e.g. if you know the scientific name, or maybe just a description on how it looks like, or a photo? This can help finding out why it didn't work.
I grew, and grow, a lot of succulents as a hobby (also on the balcony, as we have the right climate for that). From my experience with that, the roots often take a long time to grow, but the plant survives in the meanwhile and will get fuller and "crisper" once that's done.
Other succulent species just have small roots and that can look like there is something wrong but that's how they are.
Normally, what grows well in a dragon's enclosure are plants from desert climate zones. However, if you want to have a "nice" plant, you might have to water significantly more. They survive with little water, but can absorb a lot in a short time like they do in nature. However, with the amount they survive with also in nature, they don't look "as nice as from a garden center". To keep that look, you would have to water more.