There’s shuttle buses from both airports to Taksim they take over an hour though and public buses even longer over an hour and a half. I’ve booked a taxi myself for next morning its quicker 40 mins and would take me straight to my hotel in Galata down the road. But I am tempted to sack it off though now I know there’s free buses being put on to Taksim on day of the game going every half hour from early on, only problem with that would be the return booked to the other airport.