Time for that diagram again:
View attachment 92020
Right now we're very nearly at the Novorossiya outcome, just missing a bit of Donetsk Oblast and Zaporizhzhia Oblast, but with bonus land gain in Kharkiv Oblast. Landlocked was my original estimate for a maximum goal for the campaign. Note both Landlocked and Split in Half calls for gaining both Nikolaev and Odessa. Given the recent withdraw from Snake Island I'm thinking Kharkiv will be in the crosshair soon, maybe after all of Donetsk Oblast is taken.
Belarus involvement would take this further than even Split in Half. I thus don't think it will happen until at the minimum the Split in Half outcome looks to be certain and Ukrainian forces are no longer capable of putting up much organized defense. When that happens Lukashenko will probably sweep in to take some land and say "look, I'm helping!" and cover himself in glory and all that.
I agree 100% with your chart for gauging "short-term" victories.
But in the "long-term", it's arbitrary to defined victory based on land gains, because Russia didn't enter the war to gain more land, it entered the war to prevent NATO membership for Ukraine (i.e., formalized neutrality, via treaty or practicality). Now with Finland/Sweden certainly acceding to NATO, the long-term conditions for victory is different.
Yes, technically, a landlocked and militarily-weakened Western Ukraine satisfies the condition for defacto neutralization, but only in the narrow military sense, not in the political sense.
Russia can still salvage this with regime change (not necessarily full-annexation), just place a pro-Russia successor regime in Kiev. That would offset the accession of Finland/Sweden and make it a Russian-leaning mixed victory.