"Oaxaca," just like it sounds
The only glaring exception I run into in Spanish is "que" being pronounced "ke."
Doesn't seem that way to me; the native speakers I’ve known tend to pronounce the X’s different ways in:
México / Oaxaca
vs.
Xochilmilco
vs.
Ixtlan / Tepexpan
"X" in Mexican might be shorthand for sharp mystery consonant.
https://es.wikipedia.org/wiki/Reajuste_de_las_sibilantes_del...
https://en.wikipedia.org/wiki/Phonological_history_of_Spanis...
With the Serbian Latin/Croatian alphabet it gets a little complicated because it uses digraphs such as lj(љ in Cyrillic), nj(њ)and dž(џ).
People are extolling Italian here, but note that for those three sounds it uses the digraphs gl, gn, and gi.