Between flaky software/firmware, fear of network security, device incompatibilities, and the slow but steady enshitification of all the things, the industry has been a real let down.
I have a Smartthings hub, 4 z-wave switches, 2 z-wave wall warts, a handful of Sonos speaker (pre-voice assistant models), 2 HomePod Minis, one old Echo mini, and an Apple TV.
The Sonos and Echo pre-date HomeKit. The Echo only exists to add voice control to Smartthings and Sonos. "Alexa, play music in the living room" "Alexa, turn on the outside lights". Sadly, Sonos's software has been on a downward spiral for a few years now. The latest iOS app is less intuitive and reliable than the previous. And my wife's iPhone 16 Pro wouldn't connect to the network for months - I eventually had to shut it all down, hard reset everything, and rebuild the Sonos network. I'm done with them.
The Apple TV was bought for TV (duh), but serves as the Homekit base station. The HomePod Minis replaced a couple of Sonos in our bedroom (see above). But, Spotify doesn't play natively on the HomePod because Spotify and Apple seem to be in a state of corporate Cold War. So, that kinda sucks.
I'd love to add a few more light switches, but I'm reluctant to add any more Z-wave since it doesn't talk to Homekit (without rolling some sort of 3rd party bridge, which means adding another device to my network and managing it manually myself). So, I'm kind of stuck with what I have until I find the gumption to replace it all with Caseta or similar.
It's all a big old mess. But at least the shitty ecosystem has kept the house relatively uncomplicated. My wife manages to use all the things without much trouble. So I guess that's a plus.