One issue you’ll run into is that HA can’t stream music over Bluetooth (or couldn’t a few months ago), so you will have to go with a wifi speaker or preamp, or a separate server to stream the audio to a Bluetooth speaker. Or find a python package that you can incorporate into HA through the app daemon add on, or a docker image to run as an add on.
You can probably use HA to do the voice processing and send the command to the streaming server, but I haven’t played with the voice feature enough to tell you how much of a pita it would be to set it up to reliably be able to decipher a band, album, or song from a voice command. I do know that it’s a hassle to do it in rhasspy (you have to specify each option, iirc).
Once you do get it set up, you can probably set up a custom media player entity to control playback.
I’ve been checking on native HA Bluetooth streaming on a regular basis, because I want to design a whole home audio system that will follow me from room to room.
Oh, then that’s super simple with the media player entity.