First things first: for me, a fighter is exciting or not depending on what he does inside the cage.
That said, after following the sport for many years, I've watched many "face-offs" in press conferences and YT throws at me tons of reels and whatnot of fighters not fighting.
Plus the post-fight interviews, obviously.
Maybe it's something cultural, I'm Spaniard, or I'm missing nuances because English is not even my second language.
I'm approaching 40, so I was young enough at some of the times I'm referring to.
Conor (prime Conor, not... the current junkie one) never struck me as charismatic. Pre-Aldo fight he was overly loud, histrionic, annoying and disrespectful to a true legend.
Pre-Khabib, I think Khabib was the charismatic one, not even a contest.
I like some flex when you are smart, witty and can deliver a joke: DDP.
Chael Sonnen (back then), obviously. Fedor.
JG is lots of fun.
Khabib and now Islam are comedy gold and have charisma over 9000. I'm not a muslim and couldn't care less about religion.
Leon is boring as a fighter, but calling his mom in tears after KOing Usman and right next being cold enough for the "headshot, dead" punchline was pure magic.
For context, IMO Jokic is the most charismatic NBA player right now by a mile.