Have yet and haven’t yet

I’ve done some search on google and found a meaning of the word “yet” is “If you have yet to do something, you have not done it” (definition by Cambridge Dictionary), an example is:

They have yet to make a decision.” which means the same as “They haven’t yet made a decision.

My question is that in the many “haven’t done” situation, is it better to say “have yet to” or “haven’t yet done”? Do the two phrases have some slight differences?