Hi!
The problem with RPGMaker is that it’s impossible to have a working game in that engine with the restrictions on 1 sprite and 1 background. I don’t use RPGMaker myself, but as far I know that’s the main issue.
As a side note, I will be using an engine that is not for VNs either, but allows me to work within the constraints of the jam.
It would help if you specified what engine you’ll be using, by the way.