supersaiyansubtlety schriebSince it's in java, is speed a concern? Java's not known for being fast, lua is.
Java is easily 20x faster than Lua without JIT for anything that you do and could be much faster in some cases. With JIT, Lua can perform better but still won't be as fast as Java. Note that JIT is not allowed on iOS. Java is "slow" compared to C/C++, and even then Java can be faster (mostly due to how allocations are done).
supersaiyansubtlety schriebWhen I said I want as much UI as possible, I was actually talking about a UI for myself, as the programmer.
Ah, libgdx can't help you there. Maybe look at Unity, Unreal Engine, or Godot. Note we don't have a Godot runtime yet, but it is in the works.
FWIW, I wouldn't personally use Lua, as it is dynamically typed (productivity tanks because many bugs cannot be found at compile time, and a large codebase is a nightmare because refactoring tools are poor) and the syntax is a bit wacky (1-based array and string indexing is not good).