Having the same issue here, sadly I did not even selected the Alexa one, I have Alexa installed but it was never the default one.

I don’t understand how it goes to it and neither have found a way to change it.

If you or anyone gets the magic done, please share your knowledge!

Edit to update the solution that worked for me @tmC :

In case this helps anybody, coming here with the solution that worked for me. It was a silly one actually, but it did the trick.

After contacting the support, they suggested me these steps:

To resolve the issue where Alexa is being launched instead of Google Assistant, you can typically change this within your phone’s settings. Follow these steps on your Nothing Phone 2 to attempt to change the default assistant:

Open the “Settings” app on your phone.

Scroll down and select “Apps & notifications” or just “Apps,” depending on your version of Android.

Tap “Default apps” or look for the Configure default apps setting.

Select “Digital assistant app” or “Assist & voice input.”

Tap “Assist app” or a similar setting. Here you should see a list of different assistants that can be set as default on your phone.

Choose “Google” to set Google Assistant as your default assistant.

Alternatively, if Google Assistant is already selected but Alexa is still taking over, try selecting Alexa, then select Google to refresh the setting.

If you’ve done this and the default assistant is not responding properly, you may need to reset the app preferences or uninstall and reinstall the updates for the Alexa app to see if that corrects the association:

To reset app preferences:

Go back to “Settings” > “Apps” or “Apps & notifications.”

Tap the three dots (menu button) on the top right corner of the screen.

Choose “Reset app preferences.”

To uninstall updates for the Alexa app:

Navigate to “Settings” > “Apps.”

Find and select the Alexa app from the list.

Tap the three dots (menu button) on the top right corner and choose “Uninstall updates.”

In the end, uninstalling the Alexa app, reconnecting the Ear (2), and reinstalling the app after setting the Ear (2) did the trick for me.