Suggestions for working in Japan

Japan is not perfect.

As a foreigner you will face many challenges.
In Europe everything is well arranged and many rules applies, but believe me Japanese is different.

You are still young (17) and already want to live in a foreign country, great dont let anyone stop you.
The only thing is what do you have to offer?

Do you speak the language, do you have a degree in something which can be used in Japan?
You can study in Japan and try to find out if Japan is what you really want.

Since you have a lot of free time, I believe you are not studying the language or a major study.
Japan is not a country you can just walk in and raise up your hands and get what you want.

You will need to proof yourself and compete with others.

But having a dream is a great starting point.

I would just go to the language school. Everyone here is acting like you can't get a degree online (which by the way is way cheaper and shorter time period). Especially if you go to the language school for two years and then a vocational school. Literally its possible especially with a language school.