Not to mention their collapsing demographics over the last few decades, made all the worse by the pandemic/failed invasion double whammy. Compounded with the fact that they cannot mount another such an offensive for the foreseeable future.
Even taking all Ukraine as a willing slave at this point would not lessen those defeats, and the AFU would only become a hardened insurgency if the government falls.
Russia has dashed itself to smithereens on Ukraine whether they win or not, and even that is not yet sure.