Multi-Room audio output for various functions

Hi all

I would like to have addressable speakers in each room for various purposes, these being:

notifications
music
alarms
sounds to confirm things are happening
alerts
etc

I have Echo’s in most rooms, but sending audio to them seems problematic at the moment (trying to get the alexa media player working by giving my 0.2p but it seems plagued with authentication and 2FA issues which I feel won’t get any better.

So, I have the option to use a device as a Bluetooth A2DP gateway (EG connect this “device” to the Alexa speakers) then send the audio to this device. I am not sure how well that would work unattended but it would work. I have read that A2DP on RPI can be quite problematic so I am not sure what I would use to implement this.

I did see the Chrome cast audo devices, they may work well for this purpose, and would allow me to add another set of speakers if I wanted to.

I have read lots and lots of threads and they all seem a bit confusing, if anybody could give me their advice that would be great.

in summary, it would be good if I could use the Alexa speakers that already exist around the house, but am happy for a workaround solution if sending audio to them directly is not possible. Also happy to put another set of speakers and send audio to them via chrome cast/RPI etc but obviously using the hardware that already exists is preferable.