Hoi @Ade_Bruijn ,
Your expression is close, but when you intersect the "wijken" layer with a "buurt", you obtain a featureset or in other words a collection of features even if there is only one feature. You will have to take for instance the first wijk found and then you can access the attribute that contains the name fo the "wijk".
var wijken = FeatureSetById($map, /* concept wijken(afgeleid_van_buurten) */ "CBS_wijken_afgeleid_van_buurten__3310");
var wijk = First(Intersects(wijken, $feature));
return wijk["VeldNaamVanVeldMetWijkNaam"];
There is a potential catch... it is possible that a neighboring "wijk" is also returned and to avoid obtaining the wrong "wijk" name you could do a negative buffer to reduce the size of the "buurt" (current feature) and ensure that you get the right "wijk". An example you can find below:
var wijken = FeatureSetById($map, /* concept wijken(afgeleid_van_buurten) */ "CBS_wijken_afgeleid_van_buurten__3310");
var buf = Buffer($feature, -1, "meter");
var wijk = First(Intersects(wijken, buf));
return wijk["VeldNaamVanVeldMetWijkNaam"];