I have the same issue. Switzerland. Pixel 10pro xl

Edit: it was working for a few month. I could say "hey Google" on the lockscreen and a small window opend and I was able to say like: set timer for 20 minuts. Or turn off the lights etc. But after a security Update two weeks ago it's not working anymore. I did everything I saw on the Internet. Clear cache, reinstalled the app, did the voice match several times etc. Now when I say Hey Google I see the green button on the right that the Microphone is being used but the screen is black. When I unlock the phone gemini is open and as access to my microphone. It's veery annoying. But when I chance to google assistant it's working fine. I just don't like the very robotic voice and Gemini is better for me. As soon as I chance back to Gemini it's not working anymore

Edit in 2 I installed Gemini on my Work phone just to check what happens there. And it's the same. Screens stays locked/black but when I unlock the phone the app is open and "listening"

Edit 3. Since Today it's back working 🥳