Am I being naive?

I'll try keep this short-ish.

I'm a 23 year old dude who just finished 8 months of SEA travelling.

i visited Japan for 2 months like most of the people in this sub reddit and started considering ways to move there. A japanese language school was recommended by most, yet as I opened the application form today I started questioning how sustainable of a choice this is. I have a degree but don't want to teach english, I have savings but that's not going to last in terms of long term. My Japanese surely wouldn't be of any use in terms of employment anyway, even if I spent two years at a language school.

Alongside this I have a product design degree, and design is 100% the career I want to pursue, and yet japan doesn't feel like the place to head for that? I'm sort of at a loss and having a mini crisis because if not Japan, then what?

So back to my main question? Am I being naive and just seeing Japan with rose tinted glasses? Or is there some way I'm not seeing in terms of living in Japan.

Honest opinions would be immensely appreciated