On a Mac now the alphabetic and digit keys do not autorepeat when held but instead pop up little menus of variants. Shifted alphabetic keys get different variants appropriate to their letter. Sadly for TÜRKİYE the single dot capital "i" is not one of them.

At least for my settings, none of the digits get options, nor do they autorepeat.

A completely useful overloading of "long press" of a keyboard key, but completely undiscoverable unless you make long strings of "vvvvvvvvv" as a pointer or some such, then you get a disappointment instead of what you wanted, but you will be enlightened.