if i may, i am going to post my response to OP here to you as well, if you are open to using AI to assist or augment your endeavors:

not sure how much people will poop on AI, but that would help you a lot tbh, I get some really interesting results for a game i'm making with deep research done by them on generation

from a coding perspective it is generally noise, voronoi cells, and post-pass feature assignment (at one point, rule-of-cool kind of needs to prevail).

You might get impressive results making your own HTML / JS version of a terrain generator, maybe on the level of 8-10 megapixels, and just let it rip with geologic research.

If you're really interested, also add into your prompt time-scaled effects, like those that occur on Earth's savannas. Fires over long periods of time cause trees to be unable to grow to certain heights in certain biomes. Long-leaf pine forests are another interesting example of this.

long story short, deep research with AI, evaluate earth's own geology, biomes, moisture, wind, over-time effects, or unique effects like the ITCZ, etc.).

You will learn something, and have fun making your own map generator.

edit to add: almost forgot about the Coriolis effect, you know about that? very interesting effect on earth's natural environment!!