How many times have you said "OK Google" only to have Google Assistant respond with silence or in such a soft voice you couldn't hear it?

Never again!

Volume Control for Google Assistant lets you set the volume level of Google Assistant separately from your phone's volume. That means Assistant will respond in whatever level you choose even if your phone volume is low or on silent!

Simply allow the app access through Accessibility and set the options as you like. That's it! Next time you use Google Assistant it will use your volume settings.

Volume Control doesn't require any permissions other than Accessibility turned on and it saves no data about you.

https://nyelito.github.io/VolumeControl/