Here is an old (2016) breakdown of their income sources: https://krita.org/en/item/funding-kritas-development/

I follow their updates semi-regularly so I'm not sure if they made a more recent one that was as detailed. I found a tad depressing to see how much Steam purchases are making compared to donations.

They also had an interesting post about the fact that on the Windows store they cannot mention that you can download it for free as it is against Microsoft TOS: https://krita.org/en/item/krita-in-the-windows-store-an-upda...

They also mention that it's a compromise, it's adding a new income stream but participating in the economy of non-free software.

It's hard to make money with free software, even if your product is industry-level in some aspects.