Here is a link to a photo of my balcony in San Francisco during the initial stages of the virus
But at the end of the day it's the same as house, you just have a much smaller canvas to work with.
You'll want to look up the ESPixelStick to get started if you're in an apartment, it can probably meet all your needs, since you won't be able to do too many lights.
I still think it’s an idea worth considering in some situations though, as long as you are sure it’s compliant with rules from the landlord and fire safety regulations etc.
But I've definitely seen people build a false wall that covered 1/2 of a real wall to make fake builtins over a fake fireplace. But they could take it with them when they left.
It might take several days, or even a couple of weekends if you have busy days during Mondays to Fridays, to disassemble it. And that’s if you originally built the whole thing in one go and kept in mind and made notes of how to disassemble it.
The worst situation is if your lease suddenly ends on short notice and you don’t have time to disassemble it on the time you have left before you have to leave.
Another thing is that even if you disassemble it on time, the dimensions of your frame probably won’t fit well into the next room you rent in a different place. And then you have to do a bunch of cutting and maybe buying even more materials or throwing away some of what you had, or find somewhere to store it or something.
There’s also the possibility that you might accidentally damage the original floor or walls even though you try to be super careful, if you go about constructing such a thing.
These sorts of potential complications are part of the reason that I ended up not actually building such a thing myself so far. Aside from also not having much in terms of extra cash on hand at the time to even go buy the materials I would have needed for it.
The half wall you suggested is far more practical for sure.