Will there maybe also be one of these for the Battle UI too in the future? Maybe as a separate plugin or update? Because I use heavy UI design in my projects and this plugin would be game-changing if it also worked on the battle UI as well.

Hello! For the next update, yes! I'm working hard to also make it available in Battle UI!

Currently I just also finished implementing the Title Screen editor in the very same plugin! This means the next work I will be adding is the ability to also customize the Battle UI!