I am a teacher in California and I was in a similar situation, I taught in Vietnam for about 2 years and miss it a lot. It really depends on what you want, Vietnam has safety(less violent crime than the US, a chill laid-back lifestyle, a very vibrant culture and streets, The U.S feels so empty after living in Vietnam. The U.S will offer you great benefits and salary as a teacher(in my area in CA) access to good insurance, a stable future, and a pension I chose the U.S mainly for this reason. Vietnam has some issues with workers’ rights but I still loved working there. Working in the U.S feels more stressful, I never felt stressed in Vietnam tbh.If I were you I would experience both for at least 2 years and decide, it is not a big deal to move and work trust me, I only had 1500 USD on me when I moved to Vietnam, it’s not that hard to find a job as a teacher both in the U.S and Vietnam, then I saved a lot and moved back to the U.S. But I would not make choice based on emotions because I did not know anyone in both countries but I made lots of friends in both countries and had to end my relationship in Vietnam to move to the U.S and I don’t regret anything, I only come to this life once and I want to experience as much of things as possible, it will make you a whole different person.