People are saying how hard it will be to train ukrainian tank...

People are saying how hard it will be to train ukrainian tank crews to operate the main battle tanks the west is sending. But presumably most of the crews will be familiar with operating tanks (though soviet). Also I understand there are 3 crew in a tank each specialising in a role, like driver, gunner etc... So I wouldnt think it differcult to become reasonably proficient. But I am guessing becoming a proficient fighter pilot would be a lot harder and take alot longer.