Erdogan is unpopular and the economy is tanking. Turks want him to resign
There’s no clear cut alternative that will beat him in the first round. He will win it no doubt but not enough outright.
Even in the second round, it’s no where near a landslide against Erdogan. Imamoglu of the CHP is polling at 58%.
Furthermore, the second round polling has been really inconsistent recently. We have been seeing swings against and towards Erdogan.