Beterbiev may be the better fighter pound for pound and might win. But we’ve never seen him take a heavyweight punch or at least not publicly. Maybe he has in the gym but who knows. And Johannson could hit very hard.
Give what a whirl? There are guys the size of Johannson at light heavyweight like Smith and Benavidez I am unaware of any 6'0 196 pound contenders at heavyweight for Beterbiev to fight
Other than a couple of extreme outliers, no. The average LHW today is mid to high 180's on fight night, which is around 10-15lbs lighter than Ingo would have weighed in the ring.