Oh boy, I think making any changes based on numbers is the riskiest thing there is. If everyone followed the norms, we'd have very little diversity in media. Especially when the norms prioritize the actual author and their work last. I'd say if you didn't split your chapters before, there was likely a logical reason. Maybe it was a lapse of judgement and you really could split the chapter, but I think it's more important to have author intent and integrity than bow to an algorithm. The real question is; why did your chapter end where it did? Why didn't it end before that? If your chapter is too long, readers would have to be engaged already to determine that. The worst case scenario is they don't finish the chapter. If it's short, they may finish it, but who's to say they don't get to the same spot and stop reading? The only benefit, I assume, to shorter chapter lengths is maybe the algorithm? But if the algorithm jumped off the bridge, would you jump off too? At least when publishers and editors have suggestions about things like this you might be on your way to a fat paycheck, but I'd trust your gut.
Remember there are no hard rules in writing. I checked out your chapters, and I'd say the real issue is the one line at a time thing. That can make it seem longer than it is when the human brain is more accustomed to reading things quickly. Another reason why 10k isn't too long for a chapter. I can't see why any actual reader would be like "nooo there's too much of this story I like." As long as your pacing is good, and you're not meandering, you should be golden. I'm not sure what global attention spans are in 2026, but so much of modern writing is based on short attention spans. If that's paramount to you, capturing that audience, then you certainly have to write punchier, but if you're just telling your story, and this is how it is, I say keep doing what you're doing and your audience will find you. I don't think short attention spans are killing reading. I think bending over for short attention spans is alienating the more diehard readers. Nobody's going to the bookstore and counting the words in each chapter before they buy it.