It depends what exactly you mean with efficiency. In this case, efficiency and reliability matters a lot, especially for an army like TSK who doesn't accept half finished products. The same happened with Russian SU-57. The reason why we don't see SU-57 entering into mass production was due to unfinished engine, with AL51-F1, they kind of achieved the requirements, hence the project starting to speed up.
There is only 1 exception where Turkey can throw out the efficiency and reliability problems from window, if they fail to buy American Engines for block 1/2 of Kaan, they will be out of many options. If American engines are out of the window, there are only 2 capable engines where Turkey may look, South Korea and Chinese WS engines, which i  personally think they will not choose to go with Chinese engines.