Hi there! Just some random recs, because I don’t know what styles you like:
Say You Care dreampop-slightly emo rock: https://sayyoucare.bandcamp.com/track/–2
Yuki Lovey 勞嘉怡 dreamy indie-folk pop, this one is gorgeous: https://www.youtube.com/watch?v=ZtFGwPxaXXA
2-halves 芊彤說 芊蕾說 sisters playing sweet folk: https://www.youtube.com/watch?v=o1JSrT6rkOA
Ellen Joyce Loo 盧凱彤 Lu Kai Tong (卢凯彤) has released songs in both Cantonese and Mandarin.
Denise Ho / HOCC 何韻詩 (you probably already know about her.)
[Looking at my Hong Kong bands list, I realize that it is almost all female vocals. Many of the HK bands I have with male or female singers sing mostly or all in English]
Hopefully you will enjoy some of the things I linked. Let me know if you want to narrow it down to a particular style. (ballad, punk, metal, etc.)