There is a piece of software called FPS Creator which I used when I was much younger to make 3d shooter levels, and it does not require coding. You can drag and

There is a piece of software called FPS Creator which I used when I was much younger to make 3d shooter levels, and it does not require coding. You can drag and drop assets, and there is existing scripted behaviour for enemies and doors, etc. I see that company still makes modern equivalents https://www.thegamecreators.com/ https://www.thegamecreators.com/ But my general recommendation is to maybe start with something which is more of a 3d sandbox and level editor. That gets you the 80/20 value.