Why doesn't Ukraine just accept Russia s terms? Putin states all of Ukraine belongs to Russia. At what point does one accept the war cannot be won?

It s been 3 years already. Ukraine has fought valiantly but looking at the data Russia has no reason to stop and is gaining ground gradually. Ukraine should trade liberty for security and sue for peace terms. Eventually I think the entire front like could collapse if Russian forces take Odesa especially Ukraine would become a landlocked country essentially.