Beterbiev is a stone cold KILLA:dead His injury healed up nicely so this is going to be fun while it last:bbb Beterbiev by TKO in the 5th:deal
I imagine he will probably stop Barrera, and he of course has the power to stop Kovalev, too. But I think Kovalev would be too good for him. Kovalev has a much better jab, and is better at setting his punches up. I also think he has a far higher ring IQ.
I personally think Kovalev's far superior jab would be the difference maker, myself. But if Beterviev can neutralize that jab, then what you say is definitely a possibility. And with two guys with this type of power, anything can happen. But in these type of situations, I tend to believe the fighter with a better jab will have a better chance at delivering his devastating power shots.
Barrera is on the record saying he wanted to fight in the summer too and stay busy, just couldn't land anything. He will fight anyone, props to him but he will get stopped because he's too slow on his feet.