I have the same issues starting a few weeks back. It looks like emulated_hue stopped working on the Alexa side. All input_booleans that I have used for 2+ years become “unresponsive” on the Alexa app, and trying to add them back is futile.
I have now set up this: GitHub - t0bst4r/home-assistant-matter-hub: Publish your Home-Assistant Instance using Matter. as an alternative. When I first set it up, it was somewhat flaky. It seems to work better recently, although I haven’t really “stress test” it yet. (See my post here)