Whole home audio - multi zone/multi source

Hi all,
I am very new to HA and still doing quite a bit of research before set up. Please excuse me if this has already been covered (or this topic should be set to a different category).
I am looking to set up HA with a Pi4 and one of my requirements is whole home audio with multi zone via multiple sources.

Specifically, I want to be able to feed say, 3 different streams (Spotify, FM, Pandora, Amazon, Local NAS, etc), to three different zones at the same time and control them all from one interface.
So, have the Room1 as one stream, Room2 as another and Room3 as another.

I have found a few receivers that offer multi zone, multi source, such as the Onkyo TX-RZ840, which can power zones 2 and 3 via pulling channels from your primary surround over wired connections.
It also has built in streaming services.

I would like to take it a step further though, and use WiFi speakers with amps, and have a central hub that can stream to those different speakers, with multi zone/multi source, and use HA as the front end interface to be the source and destination speaker selector.

Has anybody done this yet with a solid working solution? I really don’t want to patch a bunch of things together and mess around with them later down the road.
Price is a bit of a factor. I don’t want to completely break the bank, but I know this could start to get pricey.

Thanks all!

EDIT:
I have found a few different options like this:
https://www.adorama.com/bosch10w.html
https://www.adorama.com/sooneslus1bk.html

and they are seemingly independently controlled.

Reading through this post I see something similar with Chromecasts, but MPD requires Spotify premium, which may be okay.