Blachowicz is a bjj black-belt, although not all black belts are equal. And being skilled in bjj doesn't necessarily makes you great at takedowns or at keeping guys down, as most of it's focus is on fighting on the ground where both guys are willing to do so. Even looking at bjj tournament fights it's not uncommon to see people just starting from the ground. Wrestling or sambo are much better base for takedowns imo.
That being said, Blachowicz was doing good in the first round but just couldn't find that rear naked choke. Then he gassed out badly at the end of the 2nd round and was too exhausted to do anything. Still, one judge gave him a win.
I was disappointed in Jan back then, but now, looking at how Pereira beats everyone up, he's not looking so bad anymore.
But there's also a general trend in how mma has evolved, when jiu-jitsu is just not as effective as it has been before. Now everyone knows the basics of ground game and submission defence.
Lol, I searched for it and it turns out to be true (as per wikipedia). Apparently they gave it to him after his UFC 300 win:
https://jitsmagazine.com/alex-pereira-promoted-to-bjj-black-belt-after-ufc-300-win/?utm_content=cmp-true
I think that's a good evidence that black belts don't mean anything anymore.
It's just a belt nothing more to it and it's been proven that BJJ doesn't work when the opponent doesn't engage in BJJ as well. So many of the videos on YouTube about these where a striker just beat down a BJJ upon attempting. But I think Wrestling vs BJJ will be a battle on who's going to control the fight.
Seeing Ankalev is also a striker so this is going to be a striker vs striker. It's just a wonder why Alex didn't call Ankalev. Maybe becuase he got what he wanted in that division which is the belt and he wants to move up already planning to get another belt and looking for the biggest fight of his career as well.