Hey nukes. Your gear is gonna have it's own room in your new house, yes?
If so I'd forget about basses for awhile. Just keep what you have, including and especially the upright.
Instead look at getting a half decent guitar or two, some kind of keyboard if at least an inexpensive one just to use as a midi controller, an actual studio recording vocal mic, a decent set of monitors and headphones, a measurement mic, some sound treatment, a comfortable chair, and an ergonomic mouse that won't give you hand cramps.
After all that, then get another bass if you want, but don't trade the upright for it, and don't get one you already know you don't like then try to turn it into something it's not.