Mid-30s foreigner in Japan stuck at 6M ceiling. Sales background. How do I break out?

I’m a mid-30s Canadian, living in Aichi for 8 years. Engaged, so relocation is off the table.

Currently working at a small manufacturing company. I handle production plus international sales. About 55 hours per week. Made 5.5M JPY last year. Progression is slow and I see the ceiling at 6–7M if I stay on this path.
Japanese is business level. Strength is sales, especially cross-border B2B. NISA maxed, starting iDeCo, taxes optimized. I’m not looking for passive investing advice.

Goal is simple: materially increase income in Japan.

Constraints:
Cannot move cities
Willing to work long hours
Comfortable with risk if upside justifies it

Ideas I’m considering:
Commission-only sales roles
Starting a 個人事業 tied to international sales
Used car export as a side business

My concern is that even switching to a pure sales job still caps income unless commission is meaningful.

For those who have broken past the typical Japan salary ceiling without relocating, what actually worked? What business models or sales structures scale here?

I'm ready to do what it takes.

EDIT
I have a humanities visa for 5 years, I will eventually get the spouse visa if necessary and PR later.
10mil + in investments and savings, it will increase by itself in the future, but I also want to make more to add to the pot.

Thank you for the advice.