Something I did once a very long time ago in Corel Photopaint...

I created a sandwich of texture layers starting with base rock at the bottom, and going through boulders, rubble, pebbles, grit, sand, soil, short grass, long grass, scrub, bushes, and trees... the whole set of possible land textures up to mature forest - so that I could use it again and again as a full canvas to carve many new maps - a new one each time - by erasing my way down through the layers to 'reveal' the image in my head in that moment.

I was going to make a webpage thing of it - interactive doodle maps... but like with most of the ideas I have it just never happened that way, and was shelved indefinitely. That was about 20 years ago now, but the concept of starting with everything and erasing the things that aren't needed has stayed with me, which is why it seemed like a good idea to use this technique here with this map, rather than having to overcome the 'white page syndrome' in a piece of software I know practically nothing about.

I can see the error of my ways, now, though if I had more than just a lowly laptop, it might just have worked out ok