I agree with op who said that they aren't getting better but calling it stagnant is more than I would say. The build quality was quite high and they clearly focused on that, and the price reflected that. I own another mechanical keyboard that I bought from Amazon during the pandemic and I already started getting ghost tapping (I only used it for dev work so I was more than a little annoyed to see it).
Not saying it is perfect though. They clearly were a Windows-first shop and that never changed. I've never managed to get the 変換 key and the other Kanji keys working in Linux or on Mac, much to my annoyance.