Bharat, Airavat, Mahavideh Kshetras
There are 5 Bharat Kshetras, 5 Airavat Kshetras, and 5 Mahavideh Kshetras. Kshetra doesn't mean earth, but refers to regions. So 15 karma bhoomis in total, which mean that humans have to work. It doesn't mean Jain dharma is everywhere in the region, but it is practiced.
The 5 Bharat and Airavat regions are identical in nature, besides that of from my guess different nav grahas, minor stuff, and the fact that hundavsarpini may not be present on all.
Since our Bharat Region has earth, where the 24 tirthankars lived and spread Jainism. I would assume there are 10 earths in total.
Now for MVK there are also. I assume that there are also 5 earths in each of their kshetras/regions. Each earth being divided into 32 Vijays, which is needed due to the sheer population and size of humans there, with the earth being of huge size also. Also, but not sure of this, just as Bharat and Airavat regions have their cosmos and khands, MVK should also have such.
Is it fair to say that within the 15 karma bhoomis there is the existence of earth to serve as the central hub for tirthankars, sadhus, sadhvis, etc. But within even those kshetras there are some other plants and lands where Jain dharma isn’t practiced?
Side note:
I’m sure they all have places such as Mount Vaitadhya where their respective vidyadhars live. Speaking of Bharat and Airavat Normal humans are the only type to exist as of rn, I think the other type of human no longer exist or maybe they do but they just don’t leave their land. If they do is Jainism present in such land rn and are there Maharaj Sahebs there?