How about considering switching to IT and learning SAP? Japanese majors can consider working in Japan.
Sap training costs are relatively high, and the price on the market is not cheap now. One thing you said is that the training content is very limited, that is, the company only trains a small part of what you need to do. Another is how a layman can find such a company to train you if he wants to transform. Nothing for nothing. If you really want to know your situation well, you must attend the training. My city has SAP training in Japan, and there is a great demand for SAP talents in Japan. You can go to work in Japan through the assessment of actual projects, and newcomers can join as long as they work hard. In fact, if you have IT suggestions to learn Salesforce, the class hours are short and the tuition is relatively cheap.