Having him never exist is a tricky question. If we take him out of the equation before Chibi, however, I think we might see results begin to emerge.
The problem with assuming Cao Cao taking China is that it neglects the fact that Wu is still around. The Battle of the Red Cliffs was mostly fought, and strategised by, Wu with figures like Zhou Yu and Lu Su behind the fire attack and Huang Gai in the actual fire-ship itself without much assistance from Shu. The collapse of Wei's position in Jing Province will be OTL, the main difference being that Wu will be the ones to take the areas that Shu held IOTL and thus hold far more of Jing. Having that foothold would make Zhou Yu's proposed invasion of Yi Province a lot easier as well, and actually viable without Liu Bei refusing to allow Wu crossings on account of familial ties with Liu Zhang (his actual motive being to take it for himself) and the latter's regime is unlikely to be any more stable than it was IOTL.
Add on the officers under Liu Biao who joined Liu Bei from the former's death to the latter's establishing himself in Jing going to Wu instead and you have a formidable opponent to the South of Wei. Instead of the Era of Three Kingdoms we have the Era of the Two Kingdoms. Both sides have defensible terrain, firmly established forts, and skilled officers to throw at one another. It'd be a cold war with a series of proxy battles, each side hoping to wear down the other until they break and they can rule the land.
The survivability of each state relies on whether butterflies help them. Yong Kai's rebellion against Shu IOTL failed after he was assassinated by a fearful Nanman tribe chief, but he might be facing officers with more military skill than Zhuge Liang ITTL such as Wei Yan, Lu Meng, and so on. Both kingdoms would soon face issues over the next few decades. If Sun Deng manages to survive his illness ITTL then we avoid the Crown Prince Affair and the later civil feuds and chaos that destroyed Wu from within. If Cao Rui survives long enough to either A) influence Cao Fang towards a better character than OTL or B) replace him with Cao Mao or someone else more gifted, then we might be able to see the Cao consolidate their hold over Wei.
Of course, if either happens then the other kingdom will be more able to launch an invasion. It's hard to say. Then we have the other issue of potentially no Romance of the Three Kingdoms, or a viable counterpart to it ITTL, which causes enough butterflies that it's very difficult to ascertain what might change and what might not, especially when adding the wider butterflies from a longer-lasting Cao dynasty or Kingdom of Wu.