Is Zagreb not famous for the Visual approach on RWY23?
Nope, that would be Split, 150 miles to the south.
Regarding Zagreb, highest MSA is 5100 ft to northwest, due 600 ft tall TV mast stacked atop 3500 ft mountain. Otherwise not much high terrain around. Vectoring quality is fair, except for some old hand ATCOs who clear you for "straight-in" ILS approach runway 23 with about 120° between your heading and localiser course. Taxi carefully, driving on the apron is generally kamikaze-style.