No successful professional military has ever worked like this. Basically you want a an army comprised mainly of fanatical nationalists whose only purpose is to ‘serve their country’ (whatever that means). Hate it to break it to you but such a force would more closely resemble the Waffen SS, rather than the citizen militias of colonial America or ancient Greece. A modern professional military should mainly made up from balanced and educated professionals to be effective. People like this usually have other choices in life and thus need certain incentives to join. Not saying serving you country shouldn’t be a part of it, but for most such people that alone is not enough.

For that you either need to decrease the general size of the army dramatically or find other ways of ‘motivating’ new recruits to ‘join’. The second options has not historically resulted in anything resembling ‘ excellence’ outside of ultra-militaristic, jingoist societies.