I got Eternal div 4 1440 MMR in about 1 hour last night from common league 0 mmr in 30 matches (without a trophy and ilvl 50 pet) so I wouldn’t say it’s impossible at all just need to know what you’re doing somewhat - it was my first time playing battle arena and I’d never tested my build before… This guy is obviously on a fresh account to try and get good stats + he is a charge/vortex Tank warrior. If the AI is not set up he will demolish his opponents, he has a silence trophy as well so he can silence them, charge at them and they won’t be able to cast spells until he is on top of them casting his own spells/procs.
I’m not saying that’s what Sabotagex has done as I don’t know, but after a quick glance I can see in the hands of a capable player he can easily get those stats with his build.