Resetting ATV - stuck on ‘Waiting for update server…’

I can't seem to find any definitive support documentation or process for this, so asking here... Having just purchased the new ATV, I set about resetting my last gen 4K ATV (on the latest 14.7 tvOS beta).

It’s currently been stuck on the same screen for approx 1 hour with no progress (on the on-screen progress bar):

"Waiting for the update server…
Downloading the latest update…"

The ATV is hard-wired to a router with a 1GB connection (which is working fine).

At this point, can either reset/update process be cancelled (if so, how?), and/or is it safe to unplug and reboot so that I can try again?
Resetting ATV - stuck on ‘Waiting for update server…’
 
 
Q