I had a lot of fun making my (somehow) first fractal / Mandelbrot program, as slow as it is with higher iteration times / slower computers, but I was still energized and excited to try again in a different way, so I brushed myself up on my shaders and made a sequel to this Mandelbrot Set program instead using GLSL! It's (obviously) much faster, despite still running in HTML5 / JavaScript and made in GameMaker! I also figured out how to get the zoom to automatically shift the pan values to make sense / keep whatever is in the center in the center. I'm very happy with it.
https://gunnar-clovis.itch.io/robots-dream-of-mandelbrot-2-electric-boogaloo