Let's review the progress since last February.
Russians forces retreated to annexed territories after Ukraine received modern weaponry to replace their aged soviet era arsenal, anti armor, 600 donated tanks and HIMARS caused mass retreat to annexed territories.
Ukraine receives aid package, tanks, armor and more potent and long range bomb that can be launched from HIMARS the GLSDBs with range of 150 km ,
(source) which can hit Mariupol, Crimean bridge the only one left and other targets. Picture related
View attachment 4305342
Russian forces stationed in Crimea are fresh conscripts from the region. Same Applies to Mariupol. When the military bases get targeted by GLSDBs, archer artillery systemx and regiment of tanks Ukraine can cut off only source of units, supplies and units to the region.
Ukraine controls water plants in Krakhiv which supply 80% of the water to Crimea.
I don't know if you know much about military, battle of attrition and what happens when a bridge bound region gets cut off from all supplies. Only route left is sea of Azov, supply routes for ships go through NATO choke points.
Considering the fact Putin failed his two day liberation plan. Fresh untrained conscripts can't do much to artillery fire, much less cross the body of water to territory controlled by Ukraine.