But if it’s like Beat Saber, then a chart editor might be overkill. I’d recommend you write out how your game actually works (or will work). That might get the creative juices flowing and give you ideas on how to make your chart editor - or a similar level editor system.
It’s an exercise in programming called “rubber ducking”. The idea is you explain you problem in detail to someone else, and in doing so often come to a solution to your problem due to the thoroughness of your explanation. Often developers put a rubber duck on their desk to talk to - hence the name.