The alternative is fight a battle you have no chance of winning, all the while the area gets completely fucked up pretty much permanently.
There was opportunity for a peaceful resolution and they turned it down because they thought they could win, then the west (which had been egging them on up to that point) suddenly fucked off to do a genocide in the middle east leaving them high and dry.
At that point you would have no choice but to admit you fucked up and would have to accept worse peace terms. This isn't a video game where winning is the only thing that matters; people's lives are on the line. The longer you fight the more people that die, and for what?
And what do you think will happen if they surrender? Do you really believe it will all be peace and kumbayah for the citizens? I take it you read the news so you know that kids being "reeducated" to love uncle putin, rape, killings, is all on the table.
Do you really believe Putin will actually uphold any agreements made in whichever peace treaty signed? If you do, I have a nice bridge to sell you.
Do you really believe Putin will then say "okay, this has been enough, we're good now"?
We're talking pretty much a "mob boss with nukes and a plan" type of person here, so yeah, you keep fighting for your freedom
Edit: unless, of course, you're one of those tankies that love uncle putin as well.