The delay is inherent in a Sonos environment. It’s needed to achieve synchronised play across multiple speakers and that buffer is still present in a single-speaker Five setup.
Even a soundbar like Arc or Beam has a small buffer for tv input, though it is less than on Five etc’s line-in source.
Nothing has changed: all analogue connections on Sonos have the delay. The only way to not have the delay is by using the HDMI port on the Beam, possibly through the optical adapter.
Sonos just doesn’t make any device that could be intelligently used as a Public Address device. Better to look elsewhere for that sort of functionality.