Well I mean this is sample size 1. Not possible to say how much the test results were affected by the phones not landing exactly the same way. Maybe one was weakened by an unlucky early drop and then shattered faster? From this, I would not generally infer that one is "better" than the other. But it is still plausible
In the stress test video on the JerryRigEverything YT channel, you can tell that the back is much easier to shatter than normal. That does kind of make this seem suspicious.
"Yeah, just pay for another subscription service because the build quality of your new $1000+ flagship device is so shit it will shatter if you drop it and you'll need to replace the whole thing"