- the chances that the parliament can do it are zero
- the chances that the army can do it are small sicne he put in charge his incompetent but loyal people and has created his own military branch for his personal protection
- the chance that public protestsc could do it are also small
China has more influence on what Putin ca n\t do then Russians.
I could be wrong but FSB is kept in check by Putin private army branch, the main army is kept in check by the mercenaries, the mercenaries are controlled with money, the oligharchs are controlled with fear of FSB dudes killing them. So you would need all those to coordinate to eliminate Putin.
IMO largest changes would be a military intervention after Putin gives them some idiotic order like killing ethnic Russian civilians or some extreme suicide mission.