This is my daughter's experience.
Having done marketing jobs, pub jobs, local council jobs, in UK and Spain, decided to try teaching. Did a little freelance private English teaching in Spain. (No tefl qualification).
Before 30 years old, obtained the 1-yr working visa for Canada.
Over there, did a Cambridge University tefl diploma (don't know which one, but fairly advanced). And worked in a language school teaching English to Chinese, during and after the tefl course.
Returned to UK and got a decent job straightaway in a private school teaching mainly rich Arabs.
Went off to Africa with me, got a job offer from the British Council in Sudan (Khartoum), via local contacts at the University. (Who we met at the campsite).
Returned to the private UK school for a couple of months, packed up and moved to Khartoum.
Did well there, and moved up to a management job (still some teaching) at the Brit Council school in Rwanda (Kigali), where she is now.
A tefl qualification certainly seems to be a passport to international opportunities. And you definitely get into the local culture. She now privately employs two staff (local people) to look after the sizeable house she rents in the city. And all the students are local workers, as Rwanda recently changed from French to English as the official 2nd language.
In Sudan she travelled a lot to Juba in the south for Brit Council work, and now spends some time in Bujumbura (Burundi) setting up a new school there.
Good luck with your plans!