Been working on this project for a few days, renders took one or two minutes each on my 3070 laptop
Credit goes to SRABON ARAFAT on BlenderKit for the planet template, which I modified heavily for these renders. The main things I used from his template were the Musgrave texture distortion tricks, which I used to add biomes, oceans, and other details. Besides biomes and oceans, my other main edits were changes to the shaders (object and world/lighting), the addition of an atmosphere, compositing, etc.
Now in my updated website:
The greener looking planet is due to the plants that partially cover its surface occluding the surface more efficiently, due to its savanna-like biomes