Microprocessor board suggestions for Audio focused TinyML / AI

Hi All, 

I’m trying to hunt down the best board for my new project. Basically I need the following functionality either on the board or via add-on boards. I can see a few possibilities but I haven’t had much experience so I thought it best to ask. Thankyou!

Requirements

TinyML (processed onboard) 0.5 and above Tops

Generate and encode sinewave between 18kHz - 21kHz

Microphone input

Class d Speaker out (=>3w preferably)

Low power

Ethernet (RJ45)

Not a requirement but would be greatPOEWifiLow budget