We agree: Putin does not like any reasonable outcome and shouldn't have invaded in the first place.
You have just described a deal that Zelenskyy has indicated he would accept and Putin has already repeatedly rejected — freeze the existing lines of conflict, and allow Ukraine to remain sovereign and fully arm itself.
Putin has repeatedly flat-out refused to allow Ukraine to have anything but a crippled military.
The obvious intent is to leave Ukraine so weak it can easily invaded again, so it will either bow to every Moscow demand or will simply be fully invaded and destroyed at a time of Russia's convenience.
Why?
Because Putin can NOT tolerate any condition under which Ukraine is free to be successful or independent, and especially to join NATO (which has proven for 3/4 of a century to be purely defensive).
Moreover, Putin is now stuck, as he has broken the tacit deal with the people that he can lead with corruption and adventurism as long as the people aren't obviously burdened and standards improve. Now, he's killed a half million men, the remainder are broken monsters he can't return to society without breaking it, and he can't just declare victory and end it and still keep his position (or likely his life).
Beyond those local goals, Putin has himself said his goal is to recreate the Russian Empire, beyond just the USSR territories. It is behind all his hours of lecturing on (twisted versions of) history. He will not merely stop at Donbas.
Putin also always follows Lenin's rule: "We probe with bayonets, where we find mush, we press on, where we find steel, we withdraw.".
The only actual solution is to push back so that Russian cannot economically or militarily continue, then arm Ukraine to the teeth (whatever border they end up with).
Autocrats like Putin do not stop unless they are forced to stop.
Turkey figured it out in 2015; a pair of Russian fighters violated Turkish airspace for less then two minutes; Turkey shot them down. Problem solved, hasn't happened since.
The problem is all the EU politicians are afraid of Russia breaking up, as if it will be somehow worse than Russia reasserting imperialism. EU only enforcing a no fly zone over UKR, applying the frozen RU assets to UKR rebuilding, and hard-sanctioning RU oil and isolating RU politically would do it. But they are all too politically chicken and want to kick the can down the road. Meanwhile Russia is already waging hybrid war to break up the EU.
Globally, and historically, the fight is always rule by the people or rule by the few.
If the rest of us fail to fight, everything WILL be taken from us by the few, the despots and the oligarchs. It may not be immediate and total, but it will be inevitable. Unless we fight at every step.