Giving it to Ukraine will be a great idea.
There will be no maintenance costs on it, because it will be sunk within a week of arriving in the Black Sea
The Ukrainians would refuse it. A nation at war has little tolerance for boondoggles. Unless its the US of course. Even in WW2 the US made things like this -
https://en.wikipedia.org/wiki/USS_Alaska_(CB-1)
In service for three years.