I know nothing about the governmental system of South Korea. The American Presidential system is terrible.
No. Most countries actually have two heads of state. One is what say the Netherlands, UK, France and Germany call something like First Minister or Chancellor, the head of the Cabinet that also has to represent their party interests as leader. The other is in the Netherlands and the UK a Monarch and in France and Germany a President, a head of state that is less coloured by party politics and can be more of a spiritual leader to a country.
The US combining it in one position, is usually not that terrible, but reached extremes when Trump was President.
The American presidential system isn't terrible, it just seemed like it was terrible because Trump pretty much broke all the rules of checks and balances and got away with it because of Moscow Mitch and his dumbass cronies backing him up and letting him get away with everything. ---
People come up to me... concerned.. that I'll reproduce." - Emo Philips