What do I need for whole home audio?

device !!! you mean a volume adjuster wired to the speakers .. 

Multi-zone streaming amplifier that can be run by alexa or other app.

Those whole house audio systems are all different, it depends on what the installer did and used; they are not all the same...If you are able to know and contact the installer they may be able to give you some advice...Also a neighbor that has a similar system may also be able to help....More than likely you would be able to use a 12 channel AV Receiver with Bluetooth but I couldn't guarantee it with out seeing the system and knowing more about it. Often times you can also use a Speaker zone distributor along with an AV receiver or even a stereo receiver...What needs to be taken into consideration is if the system has volume control for various zones and how that is connected...Sometimes those systems use powered speakers...Powered speakers will have a small amplifier attached to the speaker and usually a volume control close by some where in the same room...Also the impedance of the speakers needs to be considered...Its a good idea to do some research to figure out whats acceptable connecting equipment improperly can lead to blown speakers or circuitry damage and like I said earlier all those systems are different...Often taking one of the speakers out will give you info often on the back a speaker will have info like model number impedance brand etc. also you would be able to see a small amplifier attached if they are powered speakers.

Well, if you do not like any wires to be shown, then use wireless home theather like https://amzn.to/3ec8pfO but for your question, I would say https://amzn.to/3dmAYYU

Cable TV.

Streaming media services (e.g. Netflix)

DVD player.

Turntable.

Streaming music services (e.g. TIDAL)

Computer audio.

Multi-zone or multi-room equipment:

https://www.crutchfield.com/ 

Pull a speaker down and see if it has a 70 volt transformer on it.

If so then you will need a 70 volt PA amplifier to feed them audio.

Hire a home theater installer to help you.