There had been a lot of exaggerations made about the Three Kingdom era historical figures, it's understandable since a couple thousand years is plenty of time for Flanderization. The Romance of the Three Kingdoms itself had a lot of exaggerations.

I assume you're talking about martial prowess here, since it's what Lv Bu is most famous for. According to Yuan Tengfei, a popular history lecturer in China today, mounted combat back then would not have resembled how it is portrayed in modern media. In Dynasty Warriors, TV shows, and movies, each Three Kingdom general is depicted with his signature weapon, usually a two-handed legendary pole-arm (e.g. Lv Bu's halberd, Guan Yu's guandao, Zhang Fei's spear etc.). The horseman would charge into battle doing cool spinning moves with his weapon and cut down hundreds of mobs or have an epic duel with an enemy general. However, this depiction is most likely inaccurate, according to Yuan, because the technology of the day did not allow the combatants to do that. The stirrup first appeared in China in the Jin Dynasty, after the Three Kingdoms period, which means that Three Kingdom horsemen would have needed to keep a hand on the reins at all time in order to control their horses and not fall off. This means they could not have used epic two-handed weapons on horseback. More likely, Lv Bu probably wielded a much smaller weapon one-handed in combat, which would have limited his ability to mow down armies and do cool kungfu moves.

Truly powerful warlords at the time did not rely on combat abilities, but on managerial know-how and political thinking. The most successful warlords such as Cao Cao and Sun Quan succeeded by out-thinking their opponents, recruiting and managing talented subordinates, and maintaining the right relationships with other influential people. On that front, Lv Bu made some fatal mistakes and ended up getting outplayed in the game.