When Smith 'fought' Canelo he was happy to fiddle his way to a 'respectable' points loss. Saving face rather than taking risks. He'd probably be happy being the first person to take Beterbiev the distance - he might be capable of doing that - but trade out any chance of winning to do so. The opposite of Yarde's mindset. You also know how Smith will try and hurt you; the catch counter left to the head or a left to the body. He's too easy to mitigate at the highest level. Then there's his Gallagher defence: shell up and take shots on the gloves and arms. If Canelo can rupture a bicep when offered this target, Beterbiev would perform an amputation. Bellew talking BS as usual...
You think the Smith that got beaten up by Canelo beats Beterbiev? He better age him out another half decade.
Eh.... I think the speed and defense of Canelo greatly inhibited Callum from letting his hands go. The moment he'd throw a punch he'd get countered, and he couldn't find a place to land it. Whereas the speed of Beterbiev is diminishing more and more per fight and he isn't hard to land on clean. So there's going to glaring openings, and no speed deficit to deal with.
The main danger is Callum's left hook. He is powerful with it at short range - unusal for a tall rangey fighter - so Beterbiev has to take that away from him. I think Beterbiev takes Smith more seriously than Yarde and we'll see a demolition job again. Smith moves back in straight lines and does not cut off the ring well. That's suicide against AB.
Callum didn't let his hands go because he wasn't prepared to take risks. You're right, against Canelo he froze because of the speed and defence of Alvarez. Against Beterbiev he'll freeze as well, this time because of the power. Smith's issue - other than his predictability - is his mentality. I don't think he has the same dog in him as Yarde...