Some of their country, probably yes. All of it, including Donbass and the coast, probably not. After all, anybody who felt strongly about the Donbass was already there fighting. Ukrainians might well decide that they can live with a landlocked country, if the alternative is annihilation.
Russians are literally driving on Kyiv as we speak. 3 million people live there and it's the seat of government. I'm not sure what to tell you if you think the Ukrainian military is going to abandon the fight.
