I think one must be careful to distinguish between the initial promotion of the officers in that era and engineers selection in 2020. The former is by blood and the latter by merit. Similarly, knights were chosen by blood as well. These two don't represent the same things.
You have to remember that if you scream meritocracy to the Chinese, the Chinese know PRECISELY what it means. In historical China, "meritocracy" turned out to be a regional hegemony in which rich regions in Jiangnan would have ended up dominating the bureaucracy because rich Jiangnan-ese could fully educate their youths in a traditional literary culture. The Ming and Qing Emperors noted this trend and deliberately set quotas to end their domination.
When Brahmins talk merit, they're basically talking about their caste advantages, but disguising it as something else. It's not merely the access to education, but the culture and "habitus" that enables better academic results. For instance, in an adoption study, what was found was that being raised in a nourishing, both physically and mentally, environment resulted in an IQ gain of around 10 points.