How could I find a job with only an advanced college diploma

I have an advanced college diploma in a computer engineering.

So basically I want to move to Japan next summer for 4 months potentially more, but I can't apply for the JET program as I don't have a bachelor's degree yet( I'm planning to start one in September of next year). I heard that there are other ways to get an English teacher or assistant English teacher job without a bachelor's degree, but I'd have to apply directly to the school and I don't really know how I can find Japanese schools that I could teach English and apply for my own Visa.

I want to apply for the working holiday visa but I don't think I could save up enough money to comfortably live for 4 months in Japan without a source of income. Is there any way for me to find a part-time, online or any sort of job that I could either do in Japan or online anywhere around the world(I'm looking for that one myself)

Thank you for the potential help.

Tldr: how can I find a way to support my 4-month holiday in Japan?