Lee is not in his class atm. Cowboy is entering the class of fighters that soundly defeated him throughout his career imo. Lee doesn't have the heart, cardio, or skillset. Cowboy is the better striker, has the better cardio by a country mile, and has grappling that's just as good as Lee's, if not better.
Cowboy chews him up. If Lee was in there last night he would've easily quit a few times in that fight, and would likely be TKO'd before he had the chance to. Lee has the potential to evolve and if he can fix his glaring and huge detrimental issues, maybe one day that could be a more even and intriguing fight.