Up-to-date Kindle vs Apple vs Nook market stats?

I published my first novel on Kindle (+ paperback) a few months ago, to modest success. I’m considering publishing on the other platforms to boost my reach, but am not sure how to estimate the value-add.

Most of the existing literature on platform marketshare is super old, or some forum user’s opinion. Does anyone have reasonable recent, reliable market share stats? Thank you!