Against the background of previous experiments with power projection, this self-restraint does not look entirely reassuring, and Putin has apparently concluded that such restraint does not pay.
Putin is effectively committed to continue taking additional proactive steps, which come with risks and costs that most European politicians would generally find prohibitive. Russians may currently seem far less cost-conscious and risk-averse; but historically, no ruler has been able to correctly judge the moment when the Russian population suddenly decides that “enough is enough.”