"If you want to be truly accurate to China's religion, you would say Confucian-Taoist-Buddhist. " This is just patently untrue and anyone unironically familiar with Qing history would scoff at the idea of Taoism or Buddhism embracing some kind of state hegemonic endorsement coequal to Confucianism, where reverence of the Buddha would be even close to the important of Confucian ritual.
I have no idea why some people like to combine the Three Teachings as a coherent and dominant orthodoxy that permeated Chinese history. The only period where this Confucian-Taoist-Buddhist idea of a state religion is even somewhat true is the Tang dynasty. But the rise of Neo-Confucianism in the Song and Ming period should firmly put any ideas of the Qing state as exhibiting "state Buddhism" into the trash bin.
To be clear, Buddhism was not disparaged by the state that much and there were many Chinese buddhists. But if you want to go by "actual practices" than Chinese Folk Religion > Buddhism and Taoism additively, so I don't think going by that definition is useful.
Honestly saying that the Qing Empire's religion should be "Confucian-Taoist-Buddhist" would be like saying that the Ottoman Empire's religion should be Sunni Islam-Orthodox Christianity (frankly, those two religions' historical origins are at least more similar to each other than Confucianism and Buddhism, even if Confucianism and Buddhism were able to coexist after Buddhism's golden age in the Tang).
If we can include Shintoism and differentiate Orthodox and Coptic Christianity then there is no reason that the Qing population needs to all be the same religious group as Sri Lanka.