The hardware is rather straightforward, something like a Raspberry Pi with off-the-shelf mems microphone module, powered Bluetooth receiver, battery + management (if you want it portable), and potentially some UART/SPI interface for more specific sensors/comms. The software I don’t have any direct experience with, but potentially something like Ada from HomeAssistant would be functional and easy to implement/integrate.
Is there a particular part of this that seems most challenging for you? Would you be interested in developing something to fill this potential gap? I’m toying with a lot of the same tech right now, I’d be glad to contribute.