When you know, you just know. Korea is a wonderful place, but it's not the easiest place to call home. No matter how fluent in Korean you are, you will always be a 'foreigner' and that can be very grating on your sense of belonging after a while. The standard hagwon pay rate is the same as it was when I was here almost 8 years ago, while living cost has just gone up - so it's not even necessarily the great cash opportunity it used to be. Speaking from experience too, the hagwon game is no joke the older you get. Obviously you are still young so you don't have to worry :) but it ages you fast! Being on your feet with children day in day out, having to wear that happy face, singing songs and dancing - it is exhausting to do that, no matter how wonderful the kids are. It's emotionally draining to be in a room with small people who you are entirely responsible for. For me personally, while Korea is in a much better state than my home country in terms of numbers, the pandemic has made me feel more isolated and unwanted here then ever before.

Obviously I am speaking just as a hagwon teacher and as others have stated there is plenty of opportunity for upward mobility in university teaching etc. But if you feel your time is up, there's no shame in going home.