use qt string literals
https://develop.kde.org/docs/features/configuration/introduction/ for accessing things like groups in a config, qt string literals should be used or else the compiler spits out errors, so
using namespace Qt::StringLiterals;
along with i.e.
KConfig cfg;
KConfigGroup cfgGroup(&cfg, u"MyCoolGroup"_s); // instead of just cfgGroup(&cfg, "MyCoolGroup")