What is it called when a government is controlled by one political group which suppresses all opposition and controls many aspects of it's citizenship?

This form of government is called a totalitarian regime. In a totalitarian state, a single political party or leader wields absolute power, suppressing dissent and opposition through various means, including censorship, Propaganda, and state-controlled media. Citizens' lives are closely monitored and regulated, with the government exerting significant control over personal and public aspects of life.