International student concerns

I'm an international student with an NZ citizenship and currently taking my GCE AS levels in Singapore (Y12), I will complete my A levels by 2025, even if I assume resits.
The problem I have is that I don't have GCSE results. I was in South Korea during my elementary - middle school years, hence the only grades I have would be Korean domestic school grades converted to A, B, and C.
1. would it matter so much to unis that I have an educational record thats quite frantic/pieced apart?
2. I'm considering the UK, Australia, Canada as my main application countries. (the US was excluded since I'm not really an active typa student). Any advice/tips for me to build a more 'desirable' profile?
3. Advice for prospective law undergrad in general