In the various forums I read, you are not the only person who credits a UniFi network for significantly reducing or eliminating HomeKit issues. Not sure why the UniFi network is “mo betta” than any other good-coverage system such as, for example, a mesh network, but the posts are there to support this theory.
Even with my very limited number of HomeKit items as least one a week goes “No Response” in the Home app, frequently in conjunction with the almost-monthly network software update. I looked into changing out my home network (8 eeroPro’s in a WiFi 5 mesh) to a UniFi replacement. I came away from their website with the impression that I’d never be able to do that on my own. I couldn’t even determine what equipment I’d need. Apparently this industrial-strength networking requires industrial-strength networking experience, something I find confusing at best and at worst not doable.