While I haven’t had a personal project to work on, I have been stretching my skills in Unreal Engine by following a tutorial series on how to create a turn-based battle system for RPGs and just today I started exploring the engine’s 2D capabilities.
I also helped another friend work out an issue on a project we have been collaborating on (I still consider it his project despite my contributions).
I hope you keep working on these small mechanics! Even if they don’t make it into the final game, they will help you gain further mastery of the engine, and instead of having to build everything from scratch you will be able to mix together stuff you’ve already made.