Your solution of surrender and ceasing to exist is always open to a country being invaded for conquest.
Many humans don’t share your willingness to submit to force.
Many humans don't share your willingness to submit to force.
This is a common attitude. We last saw it play out in a big way in Berlin in the summer of 1945.
This attitude was generally considered on of the biggest and most destructive mistakes in modern military history. It reduced German cities to ashes and resulted in the unnecessary deaths of over one million German men women and children
History also shows that this fight on to the bitter end mentality is pushed by the dead enders in leadership who are going to wither be killed in the final conflict, commit suicide at the end or be hanged as war criminals if captured.
The mindset is not uniformly shared by general population, many of whom just wish an end to the war.
I'm pretty certain that a plurality, if not an actual majority, of Ukrainians would be very much in favor of a cease fire and negotiated peace.
It's the outsiders who are are driving the war who have been and still are blocking a peace agreement who are preventing negotiations, not the Ukrainian people.