Yeah, he's spent a lifetime competing in fights that are three, 3 minute rounds so it makes sense that he has about 7-8 minutes of cardio in him before fatiguing, when you consider the additional 1 minute break he would get in Muay Thai. Basically he hasn't or can't adjust his cardio to MMA optimally even after all this time. Which is common, many wrestlers careers fail because of this as well. I didn't like Fiziev's ability to get extension on his punches either, he reminded me of an old Mike Tyson quote from his amateur days "Tyson, not a boxer who throws many jabs" I don't feel like Fiziev builds with his striking in a tactical way, he seems so reliant on his athletic gifts....which fade as his conditioning does. Meanwhile Gaethje was tired but could still fight much more effectively.
I don't think Fiziev is making 145lbs very easily and he will give up that speed advantage and jeopardize his cardio even more cutting all that weight. He's also so god damn thickly muscled you have to wonder if that itself just limits his cardio ceiling. But I think if he built more off basics and was more tactical and chose to use his explosivity in key moments maybe he could get a little further but honestly...I think this performance probably makes him more of a "fun fighter" athletic, explosive and technical striker with solid takedown defense but bad cardio and mediocre defense. He also, yeah, he isn't exactly solving problems when he's out there which is so crucial to success at higher levels.