How hard is it to get a job that pays as much as more as the JET salary?

I’m very happy working in JET and might even do the full five years but I might want to stay in Japan after my time in jet. I’m not sure what the market is like and how hard it is to crack 4 million yen doing other jobs. I used to work in tech and I’m always ready to learn new skills. Is it impossible to crack a job that pays more than 5 or 6 million post JET? I know it’s impossible in education so I’m looking for a different job after JET. I’m just totally blind to what the market is like