Fact-Checking this Viral Bottle Trick

It's just application of a 'dynamic force-multiplier', e.g. cracking a whip.
Check out Orca using their flukes to create cavitation to stun fish. BOOM! Awesome. You can actually see the large momentary cavity before it collapses.
And submarines have a 'cavitation depth', above that they can't use full power because of the noise and damage the cavitation makes.
See also 'shkval torpedo' using super-cavitation to achieve speeds of nearly 400kph UNDER WATER.
About 50 years ago I saw Jeremy Yau (of Lau-gar kung fu) demonstrate the bottle technique and bare-hand brick-breaking very impressively, no flimsy bottles or soft-bricks either, proper 'blue-bricks', dense and very hard, the sort you struggle to  cleave with a lump hammer and masons bolster. Bare-hand, holding a 'floating-brick'; thwack! Clean break. Then he did another brick with the back of his wrist! Wow. I still can't do the brick one, and I know the physics of it.