A medium-sized country, on the other hand, is perfectly capable
No, no - you misunderstand me.
It can certainly happen, and has happened before - but it must not be presented as such. Otherwise it leads to later rounds of revanchist attacks by the bigger "loser".
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Russia cannot be seen as having simply accepted Zelensky's offer. It has to "take" more than was offered. Through some public theater, Zelensky must be seen as having his arms twisted into some involuntary concessions.
Russia also needs to maintain credibility.
If during 2022 Istanbul they asked for Crimea and Donbass only, then when Zelensky refused - the government had to show him why this was a mistake. They did this by demanding then in addition Kherson, Zaporozhye, etc.
Then, if Zelensky is seen as resisting the "Anchorage Understandings", and refusing to do a voluntary withdrawal - then Russia again has to show him why this was a mistake.
Otherwise the credibility evaporates. It emerges suddenly that MAYBE ZELENSKY WAS RIGHT TO RESIST the Alaska proposals, and holding on, fighting harder, until a better deal was proferred.
Every time Zelensky refuses to do something, Russia has to make him regret it. This is simply an automatic derivative of the process. Otherwise the threats become toothless.
This is why I'm saying Zelensky has to be more clever, and give Russia the off ramp it is implicitly begging for. Handover the small remnants of the Donbass, and let Russia crow about enforcing outcomes.
He would still be a hero to most Ukrainians. Sure there will be some grumbling, but he would have been able to start the reconstruction of his country months or years earlier, and most importantly stop the bloodshed.
By insisting on a total and utter humiliation of Russia (which is emotionally understandable), he pays a higher and higher price - and risks gambling the entire hand away.