Mostly pro-Russian areas go to Russia and the war ends? Yeah sounds fine to me. I would say it doesn't make all that much a difference which capitalist oligarchy they're living under, but Ukraine is probably going to be fucked over economically by the West (while trying to recover from the war) for long after the war is over, so being part of Russia is probably better for the people. Ukraine has already started privatizing assets they don't even control. Also the Nazis probably won't take too kindly to the people who accepted Russian rule in order to live their lives like normal ("collaborators"), so throwing them into the hands of those Nazis might not be great.

I don't know what Russia is willing to accept at this point, but best case for Ukraine is giving up Crimea, getting the rest of the land back, and giving autonomy to the Donbass. Which yeah that might be alright too, except for the concerns I gave above. There would definitely need to be some guarantee for the safety of the people in those regions, especially the DPR and LPR. I doubt Russia would accept that anyway. They would have at the beginning of the war, but probably not now.