I don't have much knowledge of Russia of the era, so I apologize.
We can look at what he did during his tenure as Governor of Poland, though, and we might be able to deduce what he could have done as Emperor of Russia. Many in Poland saw him as a despot who frequently sidestepped the constitution granted by Alexander I. Whenever the Sejm was suspended for five years and ordered Constantine to maintain order at all costs, he took many severe measures. He frequently replaced Poles with Russians in government posts, used the Ochrana (Secret Police) to crack down on patriotic movements.