freezing the war, establishing a demilitarized zone along the frontline, and providing Ukraine with new weapons, contingent upon Kiev agreeing not to join NATO for approximately 20 years. Also 800 mile demilitarized zone with EU troops patrolling area.
Not sure Russia will accept possible NATO in 20 years, but will reserve the right to object the next time someone proposes the sillyness. EU troops that side with Ukrainian nazis seem like a trojan horse they will see through as well. More US weapons would also seem unhelpful.
A proposal for democracy lovers would be to let Oblasts, through referendums, to choose between Ukrainian nazi rule or joining Russian Federation. Odessa and east of Dnipro perhaps limited. But return to Ukrainian national and local elections to also choose autonomy, and expel EU/nazi troublemakes is essential part of peace process that can endure.
Dnipro makes for a more permanent border that is hard to cross, and easyish to defend, and natural separation from nazi sympathizer factions.
It's very unlikely this exact proposal will be accepted by Russia.