i have never programed or created a game in my life... just how hard would it be for me to do custom level in pseudoregalia?

i absolutly love the game but i feel the game itself have so much more potential. I know this is going to be an unpopular opinion but making the combat a bit more complex and adding more bossfights and maybe rework proggresion a bit and it would be the greatest game ever created.

those goals are a bit high so i just want to create some simple custom levels in the game for now, but just how hard would it be for me to create custom level?

i have used scratch and had some succes with it, i was creating a lot of code logic in geometry dash and i was creating towers in eternal towers of hell in roblox. I love game design and i feel pseudoregalia is THE game I would like to design but i am not sure just how hard it is and where to start.

any thoughts?