Let me try:
German: Sia (sometimes painful to the ears)
French: Madonna (Used to be the biggest but is fading, Still extremely relevant)
Mandarin: Camila Cabello (Fourth Harmony are the rest of the Chinese languages no one cares about. Lauren can be Cantonese

)
Spanish: Ariana Grande ( Currently the it language behind English)
Portugues: Mariah Carey (Isnt this Ariana Grande?)
English: Rihanna (Currently on top)
Italian: Beyonce ( Slay and everyone loves ha)
Russian: Chris Brown (Tried to beat English)