Yea, I agree... Your post perfectly summarizes Putin's choices in 4 simple lines.It depend, if Minsk 3.0 recognize:
1- Novorossiyato be a free confederation and
2- the rest of Ukraine to be a ''Neutral'' landlocked country.
Putin will be gratefull to stop it's special operation. If not, he could even declare war and take it by force and laying waste on the rest of Ukraine.
Putin's Plan B goal should be to carve out as a defacto pro-Russian puppet state and sign a "neutrality" paper treaty. includes Kherson (occupied), Mariopul (occupied), Melitopol (occupied), Odessa (TBD), Kharkiv (TBD), Mykolaiv (TBD), Zaporizhzhia (TBD), Dnipropetrovsk (TBD). Ukraine effectively becomes a landlocked country.
Putin's Plan C goal should be to capture Donbass, then go the Sino-Vietnamese route by unilaterally declaring 'special operation complete' (e.g., kinsmen un-genocided, Azov fully 'de-nazified'), unilateral ceasefire and withdrawal of troops from frontlines of Kherson/Mariopoul (except some remaining forces to act as negotiation/leverage for a peace "neutrality" treaty, recognizing of DNR/LNR/Crimea), and then apply pressure on NATO to force Ukraine to accept ceasefire and terms of negotiating table.
Otherwise, Putin can go back to Plan A by full-scale war mobilization and just siege Kiev again until it succumbs to unconditional surrender, but it's unclear how far Putin is willing to escalate this conflict into national mobolization.