Work permit visa before getting hired?

Hello, I have quite a unique situation but I'm hoping someone will be able to advise me.
Basically, I'm employed by a big international company who has an office branch in Japan (I even went there on business trip to train a new joiner). I enquired the director of my department if a transfer to Japan is possible for me and she said it's fine by her but HR has to agree to sponsor my working visa. When I talked to HR, they said it's out of company policy to sponsor a visa.

There are non-Japanese people working at our Japanese office but apparently they already had a visa when they were hired. I'm trying to find some way online, some kind of visa that gives me a work permit without the need for my company to be involved in the process, but it's not so easy. Technically, I am qualified for Engineer/Specialist in Humanities/International Services visa (“gijinkoku”), but this visa can only be requested by the employer.

There is also intra-company transferee visa, which would be perfect for me, but again, my company doesn't want to be involved in the process.

I'm wondering if I could work a 9 to 5 if I were on a student visa going to a language school. My country is also eligible for working holiday, but that visa is only for 1 year and you're supposed to leave Japan afterwards, so it doesn't really apply in my situation.

I guess I would like to read some advice from people smarter than me as I'm feeling very hopeless. I would like to keep my current job, but I can't stay in my country.

Important info, I'm:
– 26 year old
– working in finance
– N2 level Japanese, I have the JLPT N2 certificate
– Bachelor degree

by cottoncandyflavor