Naval Gökbey will take some time to fill that gap probably 2-3 years
Everyone knows I'm a naysayer and that TAI have shown great flexibility on churning out versions of T625 so far; but the navalized version in only 2-3 years is probably a tiny bit optimistic. I'd say 3-4.
Regardless of the need for T625N in utility and ASW versions, AB212s being retired AFAIK doesn't really create much of a gap. There were almost already being used on old short Mekos; and those ships are now gone. AB212s were old and weren't used in the roles Seahawks are used, for years.