HomePod Mini plays music and responds on its own

I've owned a HomePod Mini for 5-6 years and it's been in the same location of my house the entire time. I am the only person who has an account linked to the device, along with my iPhone & iPad. For the last month, it's literally taken on a mind of its own where it will start responding with "Sure, I can play (that artist)" even though I've never asked "Hey Siri".

I NEVER use Siri. It will play music randomly at any time of day for no reason whatsoever. I often listen or watch videos on my iPhone & iPad usually about 5 feet away from where the HomePod is positioned. The HomePod often listens in and responds with random answers or music.

Two days ago was the last straw. It started playing music on its own at 2:30 AM (yeah I was sleeping at the time) so I pulled the power cord.

I've reset the HomePod multiple times already including a factory reset via iTunes.

All I want this thing to do is play music streaming on my iPhone from one of the music services that I'm subscribed to, nothing more. I don't need it to give me Wikipedia type answers to questions I never asked and I don't want to know the weather report in Melbourne.

Can someone please tell me how to keep this thing quiet until I want it to stream music.

Thanks in advance