Ling is okay, but a bit formal. My partner is Cambodian as well so having her help with what's "valid" or not helps a lot.

The best resource is a personal tutor, they're really affordable on Italki or Preply ($10-15/hr). I can recommend one in particular if you're interested - it's actually the same person as this youtube channel (which is also a good resource): https://www.youtube.com/@Dara-TheKhmerLesson