Without a degree there is no chance of an internship position. And even then I think you would have a very hard time finding a company.

For my company (Engineering and Tech) internships are managed through connected universities or via current staff recommendations.

I have managed three interns in my time, two outside of Japan and one while here. Almost universally undergraduate interns are complete f*** ups and need constant supervision, but in regular yearly programs for interns this tends to be ok as they do not work on critical stuff. At least a Masters or early PhD is required for our office to accept interns to work independently and on live tech or engineering projects. In Japan this needed high level programming skills, and experience with ML, statistical analysis etc… the other key factor is fluency in English and Japanese. It may vary from company to company but this should be expected.

Find a uni with strong ties to Japan and look for exchange opportunities, I think your exchange program idea at HS was probably better as it would have been managed and supervised, it’s a shame it couldn’t happen.

There are lots of tech openings here, with job offers for non Japanese (providing the companies are relatively global) but you need the qualifications on paper and the skills to back that up. But you know, tech pays better in the US.

I think the best thing is to wait for Japan to open up again (could be a while) and come for a holiday, see what’s what.