You want Russia to be given territory they could not take in war? They are unable to get their troops across the Dnieper River, so your solution is to have Ukraine allow them across for a vague promise of peace?What's more, Russia would also be -giving back- some territory, as it has some territory that is not part of the 4 regions that is already mainly controls. It frustrates me to no end that this war would never have even started if the U.S. hadn't been so arrogant to begin with, but there may still be a chance that Ukraine would get to keep a port on the black sea, Odessa.
If Ukraine gives them a free crossing of the Dnieper River for a 30 day truce, the Russians will attack immediately after the gain their new positions. There is no value in giving them territory.
As for gaining Odesa, Russia had a good shot at it at the beginning of the war, but Odesa fought hard, and Ukraine regained everything on the right side of the Dnieper.