I hate to admit, is very hard to find good cases for phones like the mi mix 3 or even Chinese phone in general. But this is good as it doesn't cover up the front camera.
Sorry for late reply.
But why rooting ?
All you need to do is download Assist Mapper from the play store.
Install it, go to default app settings > voice assistant and choose Assist Mapper as default.
Launch Assist Mapper and select your app and b...
Keep up the good work. Have not tried it yet, but looks promising.
Also I have removed my default launcher and only have Nova as default for now, but hoping to have this as secondary.
Don't risk it. It will destroy your lovely phone before you know it