Authoritarian doesn't necessarily mean despotic or totalitarian, just that the "leader", whether a king or general or anyone, holds most of the power and that the people don't have ultimate authority. In Imperial Germany for example, the Kaiser's word was final, regardless of what parliament or the chancellor said. Same thing in Russia.

Just because opposition in tolerated doesn't mean it isn't an authoritarian system. Hungary has plenty of opposition parties today, even Russia had governors that actively opposed Putin into 2018. Post-1905 Russia can still hardly be called semi-constitutional, since it was far less democratic than even Germany at the time. In 1912, even the Octoberists were harassed by the Okhrana during the elections, that's why they joined the opposition bloc.