Having the Ukrainian legitimate government agree to surrender to save Kiev (or “just” Khariv) from such a fate isn't completely impossible to imagine. And giving infantry weapons isn't going to be enough to stop Putin from doing so if he wanted. I don't know how many FОАВ[1] the Russian air force has at its disposal, but Javelin aren't gonna help against that…
And after this hypothetical surrender from the Ukrainian government, setting up a bloody dictatorship with a special police arresting, torturing and executing whoever is suspected to belong to the insurgency, relying on pro-russian locals to provide intelligence is not an impossible feat unfortunately…