Here’s a quick little video from my phone. I hold about 800w for a bit (3-second average power duration as shown on the display at the time), so actual power is a bit higher. I purposefully put a bit more forward lean into it than I normally would.
Either way, nothing concerning here. I then (without even mounting the bike) pressed forward and in the same motion, on the Wattbike Atom - same thing. I can’t really think of any indoor bike that doesn’t have some give in the handlebars.
Looking back at the YouTube clip again, it’s super obvious it just wasn’t tightened down. You can see they aren’t using the handles, so it was probably a bit loose and they were like ‘shrug’, it’ll do donkey. Or, as is also likely the case - there’s tons of things I don’t notice/realize while filming that you do later on from a different angle.
Finally, as for things on the handlebars, while I had nothing on there for this quick 2-second shot, I usually have an iPad up there (and have had since spring, I just had it removed in my pile of Eurobike junk still on the floor from emptying out the rental RV), plus a phone, and a few Garmin head units.