HomePod playing music not showing automatically on iPhone Lock Screen

Hi there. I seem to be having the same issues (for a long while now) as this person did last year: Apple devices not showing automatically w… - Apple Community

I ask my HomePod to play music and of course it works.

But the controls for it do not appear on my iPhone Lock Screen automatically. Even though it DOES for e.g., my work phone, friends’ phones that are on the same WiFi network but NOT the same Apple account.

what gives? Thanks so much for your help everyone!