Really neat! If you're interested in adding clouds to your basemap I built a service [0] which generates free, almost-live cloudmaps (with alpha channel or precomposited onto a Blue Marble image) as part of my own ISS tracker project
That's really cool! Starred so I can find it later, might be challenging putting it on the esp32 but if there's an easy way to downsize the images then it should be do-able. Thanks!
[0] https://github.com/matteason/live-cloud-maps