I've read good things about Riva.
Can you just set up a smartphone with the Amazon/Google home assistant apps on all the time, hooked up to BT speakers?
That'd be a good way to test both.
My only exposure to 'smart speakers' has been a Google Home device when staying with in-laws. The thing... well, it worked like you'd expect from a voice recognition perspective, but the audio was also totally what you'd expect from a device of that form factor. Pretty much the same as one of those little portable bluetooth speakers you'd buy in a computer centre. Fine for playing nursery rhymes for kids or background noise. Not suitable for sitting down to listen to music, or for replacing TV audio.