I was so annoyed with the bluetooth auto-switch in macOS causing awful audio quality, that I decided to make an app to fix it.

I've been improving it with feedback from other users, and I've just released version 2.

You can get it for free, which it's already the best way out there to manually change audio devices. You can also buy a license for $10 one time payment and the app automatically select your preferred device. There's a 1 week free trial for the license version so you can see if it does what you want.