Help Bringing this Jade to Glory

Hey Ya’ll I’m new here. I am in Texas 8b to start… I am a personal trainer and have been learning bonsai the last year (for real this time, not like before where id work a tree and ignore it ‘:))

At my clients house it’s under a grow light 36w sanai bulb which is like 5 feet above the plant

This Jade is about 3 or 4 years old, the soil seems mucky by the core

The plan now is to repot it into a training pot to get some vigor back… I’ll prune it first

I got Brussels bonsai soil but am wondering if i should do something like Eastern Leafs Succulent mix

The Pictures are where it is now (yep i bonsai out of my gym, and i live in a bus :))

Any recommendations on grow light height, soil, pruning… any help really