I can't help wondering if Putin knew Navalny was going to die (perhaps with official assistance) and amused himself by using Carlson to pull the spotlight in his direction.

I've seen a few political influencers who reliably follow a pattern of saying something abjectly stupid/offensive which draws mockery and attention for a week or two, and just when this attention is waning, saying something else of more substance which gets widely circulated by the same attention network. If one has a thick skin for hostile criticism, it's a great amplification technique.