i am a very good sight reader, but some things are hard to sight-PLAY, because my sight-reading is "rhythms and directions of phrases" and the more 20th century you get, even if the rhythms make "sense" the pitches might not and so then your fingers are going "wait what"

the vast majority of western performed music is really logical (at least to me) in terms of chord progression and rhythm and so I don't have trouble sight-reading the majority of things, either vocally or piano, with maybe like one or two accidentals whiffed