True, but this is a bigger war than just Ukraine, it is a war of attrition with NATO. A slow grind that exhausts European NATO and causes significant demographic changes in Ukraine (since I cannot use the other d word) even at the cost of some ground now, could be making the most of a bad situation. If European NATO is exhausted the material basis for Ukraine's continued aggression is severely weakened.In purely military tactics terms you are right. However in politics, how are you going to win a war without gaining territory against an endless stream of conscripts?
So while people are indeed more important than territory in an operation where you have limited manpower, this doesn't mean that territory is meaningless.
Sometime in the future Russia will want to get back these areas and you can be certain that they will pay x times more casualties than they did on the first time they took that territory.
Its all about finding a balance (leaning towards preserving lives/manpower). If territory isn't important then they could simply just pack up their things and return to their pre-war borders, which obviously they aren't going to do, which means that (strategic) territory is actually quite important for them
In addition it shores up Russian weakness in demographics by transferring people from Ukraine to Russia who can be immediately economically productive due to their knowledge of Russian, while EU is further burdened with housing unproductive refugees who don't know a EU language well.
Purely from a military perspective, Kherson city on the right bank is difficult to defend intact. One way to minimize loss is to use it as a fortress while evacuating civilians. either repel the aggressors there or extract a heavy toll then blow bridges. Politically, losing Kherson is a big problem. How will Russia solve it? Watch the weather and the infrastructure hits.