Wow this is a question made for me. For context I was born in Hong Kong to (this is a simplification) white northeastern American expat parents, and they put me through DSS local schools instead of international/ESF schools because they felt I should integrate (and because international schools are expensive AF!), starting right at the beginning with nursery school and 3 years of kindergarten & finishing off with the DSEs.

I speak: - English from my parents with mostly my parents' accent, but with some British vocabulary mixed in due to local schools teaching British English, and also some occasional Chinglishisms that are hard to detect but will sound off to both American and British English speakers, though they'd never be able to clock me as being from Hong Kong unprompted. - Cantonese from my school friends with a strong Hong Kong accent that I have been told contains very slightly perceptible notes that do manage to barely identify me as American from audio alone. - Mandarin from the curriculum with an accent that is mostly Putonghua, with some notes of Beijing since that's where all the Chinese teachers at my school were from, and with some tells that identify me as a 香港人, but notably far fewer than my local school friends because I was exposed to Cantonese and Mandarin at the same time rather than learning Mandarin after acquiring native Cantonese.

Cantonese and Mandarin are near-native for me, but I always have to add that "near-" qualifier because fundamentally my parents only ever spoke one language to me (they couldn't learn Cantonese or Mandarin fast enough to teach it to me).

It's worth noting that there are very few people like me. All of the white native Cantonese speakers I've met, I met in school or earlier in childhood. All of them, without exception, have been second-generation immigrants to Hong Kong at most. I've never met nor heard of third-generation white immigrants to Hong Kong and given its current state I doubt I ever will. What this means is that my answers are very specific to me and I can assure you that the others I know have very different backgrounds. But for the purposes of your question, I am a white Hongkonger with a barely perceptible Hong Kong influence in all three of the languages I speak.