Yeah, is thruth but we need to realise that russian strategy is not to seize territory. That's part of NATO's propaganda, which attrubutes the russian military objectives it does not has : "to conquer" ukraine and to "dominate" it, then, when those objectives will not be achieved (because not pursued), they can claim victory regardless the real result of the conflct.
Russia's objectives are very clear: de-nazification of Ukraine (also meaning stopping persecutions to russian-originary ukraine inhabitants) and to avoid ukraine to join the NATO. To get the donbass was not in plans but now that they got it, of course they will not give it back (also, because being part of Russia was the donbass people own expectatives).