Putin feels the need to proclaim some kind of victory by May 9, Victory Over Our Nazi Partners Day. It will take two weeks for Russian troops to get situated for this new "major" phase of Putin's war. As they get situated they're as vulnerable as an aircraft in take-off and landing. Why not pound the shit out of them now while they sit?
The move to the East was, in the West's assessment, made to shorten supply lines, which have bedeviled them, and to concentrate on the friendlier Dumbass region of Ukraine for an easier W. They also hope to establish a land bridge with Crimea to give them total control of the East. V as in Victory. They will continue to pound Kyiv by air. Russian troops still vastly outnumber Ukrainian troops but the Kremlin is augmenting its mauled remaining troops with more conscripts and mercenaries from Syria, Libya, Chechnya and Georgia to bring about the desiderata of a victory announcement by May 9. Expect more atrocities from those noble people, but there is doubt to dismissal of their impact. Mercenaries are notoriously hard to fold into a regular army and to instill discipline. Chechen fighters have taken heavy losses. The xperts say it is nonetheless a "particularly dangerous" new war for Ukraine. Since Donetsk and Luhansk are Russia-declared "independent republics why should not Russian-speaking civilians in the region be fair game for attack?