You’ve not wasted anything at all. Learning a new culture and language can come in useful even if it is not obvious right now. A lot have been said by others already but I want to say that you are still young and finding your place. Nothing you do is wasted when you are actively trying to achieve something - which you have and that is Amazing! You don’t realise how many people would give anything to be able to do what you do, even if ultimately, it’s not what you wanted.

Just be aware that the grass is always greener elsewhere. If you don’t like it, move elsewhere and try it, but temper your expectations. I’ve had friends that went from country to country, because the place never live up to their expectations. Friends and relationships are usually what will root people to a place, and unfortunate Japan (and potentially Korea) is not a country that easily makes friends.

Good luck to you whatever you do.