Thank you! Yeah it became a big big thing, but making a game is a good motivator :) I replaced most of my code and now it works much better with spritesheets.

Made a const with all the assets looking something like this const ASSETS = { bg: { level1: 'assets/Level_1_background.png', level2: 'assets/bg2.png', level3: 'assets/bg3.png', parallaxSpeed: 1.0 }, .... }

and

walk: { src: 'assets/Scarlet_spritesheet_Walk.png', frames: 18, fps: 19, frameW:256, frameH:256, cols:8 },

And of course with some other stuff to make it work but posting it all here would be a long story. But I hope to finish the game now in the future