If Mao was replaced by someone else, I am not optimistic China will hold during cold war.
First, other leaders may not agree to support North Korea during Korean War in 1950. Actually most of Mao's comrades disagreed with Mao, they didn't want to fight with USA. Then we have USA troops next to our boarder.
Then, with USA threat next to our boarder, China won't has much choice but closer to USSR, or to say independent foreign policy. That's Stalin's original plan. Stalin is best geopolitical master, he encouraged Kim Il-sung to have a war to unify Korean Peninsula, Stalin knew it will backfired on China's national security.
No one in CCP had Mao's authority, sectarianism will destroy CCP from inside, just like USSR.
Without Mao's determination and authority, radical reform is harder, sectarianism will stumble China. China won't play a significant role during cold war. US won't give up Taiwan nor first island chain. China is deadlocked between USSR and USA. The north and west side is surrounded by USSR. The east and south side is surrounded by USA. China is the battle field, the front-line of two supper power.
There are 2 series of books, which you can read, one is 美国对华情报解密档案, the other is 苏联历史档案选编. I read those books, I don't think other people can play better than Mao.
Mao is very tough, he fought for independent foreign policy and great power position. Without Mao, China won't restore P5 seat in UN in 1971, nor hydrogen bomb in 1967. Without Mao, China won't have launched Dongfanghong space satellite in 1970, nor DF-4 intercontinental ballistic missile in 1975.
Mao is radical, but he built China's backbone, which is steel, heavy industry, railway, power plant, dam, and most importantly tanks, fighter jets, Nukes and intercontinental ballistic missile.
Without Mao's Nukes, Deng Xiaoping can't focus on economy development as well as cut military budget.
I think you have a point. Personally I think all ideologies is a religion, and all religions is an ideology. And we all knew religions do not get along with each other naturally, ideologies do not get along with each other naturally.
But, China dislike religions not because CCP. China secular power control religions most of time in history, not the otherwise. Religions in China never played a significant role, never. China is not Europe, nor middle east, nor South Asia. Religions must obey secular power, no matter it's King, Emperor or Chairman.
Once religions want to compete with secular power, they better knew their position. Falun Gong rose and fell just in 10 years or so.