Normalize Special Letter Char from Various Foreigner Languages

Forgive my ignorance for not knowing the technical term for foreigner languages that use characters as

  • ø i.e. Helsingør
  • Ł i.e Łeczna
  • ı i.e Altınordu
  • ł i.e. Głogow

how could I normalize those with Javascript (write a regex), while also making case insentive?

const strArr = ['Helsingør', 'Łeczna', 'Altınordu', 'Głogow']

With the code below, I was able to replace latin based characters (é, ñ, ô, etc) but not the above ones.

strArr.map(string => string.normalize('NFD')
    .replaceAll(/[u0300-u036f,"'"]/g, ''))