Funny you say that...I actually got a response from Brian Bauman regarding it.
To the best of my knowledge, Kingmaker delays are not caused by the unionization process. Unionization requires a lot of ongoing physical, mental and emotional effort, so some indirect effects are possible, but there is little to no direct conflict between the two efforts.
I'm not close enough to the Kingmaker process itself to comment usefully on delays, aside from denying that
@PaizoWorkers is a likely underlying cause.
Let's compare and contrast Kingmaker's development vs. Grimmerspace, since both projects were launched around the same time. Grimmerspace is being led by one of the developers of Starfinder under an "indie" label. It made $188k out of a goal of $10k. They are also a bit behind, but there are key differences between how Paizo and how Iron GM Games is handling it. Iron GM makes monthly updates, interacts with their backers, and has actually delivered some of their content (a bestiary and a small adventure).
To contrast, Kingmaker made $25,000,000. The original timetable of a year to delivery was, honestly, never realistic because I don't think they realized how much stuff Owl Cat Games added. Kingmaker did have front loaded Pathfinder 1e content as a backer bonus, but the cost on that was negligible since it was all PDFs of older content. There were times when it was almost 3 months between updates.
Then there was the news that it was being delayed until April 2022 - which was first announced behind a paywall at Paizocon 2021 (late May). The delay was annoying, but
hiding it behind a paywall was infuriating. We didn't get an official announcement until
over a month later. At least this time they didn't hide the delay behind a paywall, but all I've gotten as a backer are excuses, a couple of full page spread previews, and a photo of my pawns sitting in a warehouse. PDFs aren't scheduled to be released until the physicals are being sent out, and it seems the books are stuck in editing hell right now.
If it were just delays, that'd be one thing, but it's also how they've handled backers through the whole process. I'm allowed to be angry.