I feel really sorry for you as your parents set you up to be isolated. You were not raised as Cambodian, so will never really fit in there or possible to integrate. You are also not raised as anything else though, so no natural place to go either. You can’t stay in Cambodia due to lack of recognised education and possibly language, but that doesn’t auto translate into other places accepting you.

Many expats enter this limbo of citizen of nowhere where you no longer feel as though you share the same culture/values of your own nation and also don’t share the values of the nation you are living, meaning you only kinda share values with fellow expats also in limbo. You can form your own chosen family with these people (not necessarily actual family, more friends with people in similar situations), but expat life is inherently unstable with a lot of people coming and going in life, so not really suitable for people with abandonment or emotionally connecting issues. You have been gifted no choice in this matter though and raised as a citizen of nowhere, which is a crappy thing for your parents to do and puts a lot of pressure on you to fix the problem they made (though it’s great that they gave you a Western style education, don’t get me wrong). You also have the home school problem I’m guessing of limited social interaction with people your own age, and that social development is going to be really hard to overcome, not going to sugarcoat it

It’s clear that Cambodia is not for you, I think you need to get out for your own sanity. Life won’t be magically better elsewhere, but you will always live in regret if you don’t. Countries don’t just let random people in though, you need to have a skill, so either study abroad at uni for a recognised degree in something useful or learn a transferable trade (things like plumbing or construction are often in high demand, don’t know how that factors into visas. Don’t fall into the noob trap of desperately wanting to leave somewhere but not take any actions to enable that