The lag (which you may have read about) suggests that Sonos for PA is not a great idea.
Depending on your needs, for occasional announcements just use a voice recording app and then replay the sound file. 

I used to use Google Assistant for short announcements, but this feature seems to have vanished from GA with Sonos recently (at least on my system).

Any Sonos device with a Line-In connection.

A Bluetooth mike connected to a Sonos that supports a Bluetooth input connection.

The delay/echo is going to be a problem, makes it hard to talk so earmuffs too.