To add to what others have already answered, if Ukraine accepted such a “deal”, more war would be coming to Europe.

• When Russia still falsely assumed they could destroy Ukraine in just weeks, they were already prepared to march right through into Moldova (there’s ample reporting from mainstream and non-mainstream publications an internet search will reveal)
• Intense propaganda is currently aimed at Europe’s right wingers to seed distrust and destabilize Europe and to form positive opinions on Russia
• Hungary is controlled by a pro-Russian far-right dictator, Poland just barely teetered back from the brink
• Germany’s fascist party wants “Dexit,” (and “Brexit” was a Russian undertaking, too). Yes, pro-Russian far-right parties again, both. Same old.
• Russia is working with Republicans to pull the US out of NATO and destroy America from the inside out (surprise, another pro-Russian far-right party)
• A heavily Russian-influenced billionaire bought Twitter and allowed unchecked government propaganda from Russia under the guise of free speech to aid in the previous undertaking.

I have every reason to believe that Russia will just move on to the next target and that things would be far worse in Europe already if Ukraine wasn’t keeping a large portion of Russian resources aimed at them.

Also consider that any time Russia offered a ceasefire (such agreements were accepted several times), they always used it to safely rush supplies to the front lines and broke the ceasefire immediately after, often just hours after it was instated.

So when I show up to your house with weapons and force my way in, it’s totally reasonable for me to whine and complain when I tell you I only want to take over your bathroom and you don’t like that deal? Or will you shoot me dead (or call the cops to do so) unless I leave?

I guess just war until the Russian colonisers are expelled, putting an end to the imperialist invasion. Stop the expansionary push to exploit weaker, foreign countries. It’s pretty clear-cut.