Here is the Japanese news:
Begin at 0:52 in the video. Here, Duraludon hits Kommo-O with a super-effective Draco Meteor, and you can hear the familiar "super-effective" sound when Kommo-O is hit. Immediately after, Flygon hits Haxorus and Conkeldurr with Breaking Swipe. Notice that it does not make the same "super-effective" sound (side note: interestingly, in the Japanese version, they made the sound more of a quiet thud compared to when Flygon uses Breaking Strike in the English version).
It seems that Breaking Swipe isn't super-effective against either Haxorus or Conkeldurr because of this. If it were super-effective against one and not the other, it still should make the super-effective noise. I am also almost certain that neither Haxorus nor Conkeldurr resist Breaking Strike. Especially with the English trailer, that doesn't sound like the characteristic thud of a resisted hit. Plus, if it were resisted, then Breaking Swipe's power would be completely obscene, as I am about to demonstrate. Therefore, I am almost certain Breaking Swipe is neutral against both Haxorus and Conkeldurr, making it either Normal, Steel, Ghost, Poison, Fighting, or Ground. In the remainder of this post, I will be assuming Breaking Swipe is neutral against both of them for the reasons I just explained.
Here is how much damage it does (screenshots from the Japanese trailer):
I'm not going to bother with pixel measurements, but just eyeballing it, it seems like the Conkeldurr took about 25% and the Haxorus took about 55%. I think we can all agree these numbers are accurate to within a couple percent.
I'm pretty sure Breaking Swipe crit the Haxorus. Conkeldurr is more bulky than Haxorus, but not that much. It's pretty obviously a Physical move, so for example, if a Flygon uses Sunsteel Strike against Haxorus, it does 27.8% - 33.1%, and it does 21.6% - 26.1% to Conkeldurr. These calcs are all done with Level 50, 0 EVs, and 31 IVs in every stat. Of course Breaking Swipe would do more to Haxorus, but 55% vs 25% is way too much variation. If the same Sunsteel Strike calc is done but it crits, then it would do 41.7% to 49.6%, which is much more accurate to what we see in the screenshot.
Also, if an attack hits multiple targets, it does 75% of the power as the original attack does. I did take this into account during the calcs. Again, these calcs assume 31 IVs and 0 EVs in everything and neutral natures for all Pokemon, and is Level 50 like shown in the video. It matters if Breaking Swipe is a Ground-type move or not because Flygon would get STAB (Breaking Swipe doesn't sound like it would be a Ground-type move, but Smart Strike doesn't sound like a Steel-type move so might as well account for that possibility).
If Breaking Swipe is not Ground-type move: then it has at least ~140 power (lmao). A non-STAB, 140 power, neutral move in doubles that crits a haxorus does 51.6% on a max roll. This move seems like the Physical equivalent of Snarl, which has 55 power. I'm not saying Breaking Swipe also must have 55 power, but >140 is outrageous and definitely wrong.
If Breaking Swipe is a Ground-type move: then it has at least ~95 power. This is also clearly wrong, as this would still make Breaking Swipe way better than Earthquake.
Therefore, the assumptions of all neutral natures, 31 IVs and 0 EVs in everything is wrong. They're fighting in the Battle Stadium - maybe these are rental teams? I would guess that Pokemon would provide some rental teams for players so they could jump in right away without having to find a rental team. Because these are meant to be used in competitive battles, I would also guess that the rental Pokemon have competitive items and are possibly EV-trained. Also, as I mentioned in
this post, they have messed with the Pokemon in news reveals to make them appear stronger than they are. Then again, the Lycanroc-dusk was in a wild battle and these appear to be rental teams, but hey, you never know.
If the Flygon has 252 Attack EVs and an Adamant nature: then Breaking Swipe would have at least ~70 power if it was Ground-type and over 100 power if it wasn't. So, maybe it's a Ground-type move with 70 power?
The issue is that you can modify it in any way to make the move have any power you want. If you gave the Flygon a Choice Band and you gave Haxorus and Conkeldurr 0 IVs and minus Defense natures (which again, is not out of the question given what they did in the post I linked above), then you could say that Breaking Swipe's power is anything you want. The Conkeldurr and the Haxorus are on a rental team too presumably, so they wouldn't have this, but I'm not sure if we can necessarily rule out them messing with the Conkeldurr and Haxorus just for the purposes of the trailer.
But, if they didn't, the last thing to check without being too unreasonable is that the Flygon has a Choice Band. If this is the case, then Breaking Swipe has 70 or 75 power if it's not a Ground-type move, and 45 or 50 power if it is a Ground-type move. Maybe it does have 55 power and it is a Ground-type move and the Conkeldurr has some HP investment, but at this point you're going down an assumption rabbit hole. I was calculating all of this as I was typing so I think I'm going to stop here as I do not want to go down said rabbit hole.