By your own admission, you’re “driving [yourself] insane tweaking this logo” and you’re asking for “suggestions for improvement,” yet you seem to be ignoring the consensus of three seasoned professionals who are indicating that you have legibility issues. It could be that you need to explore a different direction rather than finding the magic bullet that will turn the current iteration into a great logo.
You’ve done some things right with this logo: it works in one color, it doesn’t rely on drop shadows or gradients, it could be easily reproduced across a wide variety of mediums, etc. This makes me think that you have some experience and this isn’t your first logo. I know from personal experience that sometimes designers fall in love with an idea and try to force a solution.
The core idea of a K that shows motion is a good thought. What if the K or KK monogram becomes a stand-alone mark that was accompanied by simplified and more legible KindKit type? Think Under Armour logo. The K could then be running (which still could be tough to pull off) or with the Mercury-esque wings added.