One reason why I keep banging on about Crimea, the way i see it as a layman would be to take Crimea back, destroy the bridge and you then reduce the Russians ability to resupply their forces, you reduce the front significantly, you can then control parts of the Black Sea and also the Azov Sea thus gaining the possibility of destroying any ship or air launched missiles at source, I.E still in their launchers, It would also relieve the threats to Odesa and Kherson and enable an outflanking maneuver around the Dnipro defences?? while giving a firebase to the Russian bases / stockpiles behind the lines.