Maybe gaining territory was not really the objective, maybe not all territory is considered equal.
Also they gained 20% of Ukraine along with some of it's population, if they gained more than 400 000(or whatever the actual number is) people, then the exchange was profitable.
It would have been interesting to see how many people would the US have been willing to sacrifice had the Cuban Missile Crisis would not have been averted.
> Russia has no armour left to exploit breakthroughs
They might be fighting with clubs, slingshots and shovels, but they are still gaining ground, so either this is not true, or the Russians are so good that they don't need armour. Since I have seen Ukrainian videos with recent dates that show columns of Russian armour, I would say that it's probably not true.
> territorial gains have stalled
They have actually accelerated, remember how long Bakhmut lasted? Now they are speedrunning it, they capture something militarily important almost every month.
> no end in sight
There is: Ukraine wants to recruit 18 year olds, clearly they are at the end of their rope.
> being stuck in unwinnable war like this is a nightmare scenario
They can freeze the conflict whenever they want, the Russians don't want to because they feel that they have the initiative, that's why it's so difficult to negotiate with them.
> abandoned village in rural Ukraine
In military context small villages can have significant importance. Landfills can be incredibly important as well even though they don't have much intrinsic value.
> exchange tens of thousands of lives
Maybe that's a win for them, maybe they just want to erase military power and even if their exchanges are less efficient it might still be worth it for them because they can absorb the higher cost in lives due to their larger population. I do believe that because the Russians are more numerous and have their own military industry, it's the Ukrainians that suffer more casualties, however it doesn't matter because if it meets their objective, it's a victory.