Ask HN: What to Tell the Recruiter/Interviewer?

I am currently working remotely and its been only 4-5 months in the job. I am going to start searching for a job in Japan or Germany to relocate there.

I am wondering what would be the best answer to 'Why do you want to leave your current job?' as this question will definitely come up in the interviews.

My obvious reason is to relocate to a first world country but that's not what I am going to tell them.

The product i am working on is a huge SPA but built in jQuery and vanilla JS. I feel like i am missing out on latest frontned stack and that will definitely hit my career in the future but not sure how i should phrase this as i don't want to appear as i took a bad decision joining my current company.

Any suggestions on how should i tackle this question when it comes?