Sanctions are historically ineffective at leading to regime change, e.g. Cuba, DPRK, Iraq, Iran, Venezuela, Syria, Turkey, Myanmar, but it’s the only real measure available outside of military action.
That said Putin built his image around bringing stability after the socioeconomic and political trauma of the 90s (even though most of that stability can be credited to rising global oil prices), but with the war and sanctions he’s risking all of that sentiment amongst his supporter base.