Working freelance. What are my visa options?

Hello! I'll soon be doing freelance Medical Billing and Coding as a career, and i currently live in the United States. I saw in a few threads that work visas are not given to people doing freelance work, so I'm assuming that is out of the question. I was thinking that maybe I could get a student visa and attend classes for Japanese language? I know I would need to go for more than just the most basic and easy course, as from what I've read it seems like there are requirements for how long the course will take and how in-depth it is. I was thinking a tourist visa, but I wouldn't want to make a visit on such short terms, to where I would have to uproot and go back home within 3 months. I'd like to live abroad for a year or two to really experience the culture better. I'd love to hear your feedback and suggestions.

If you're going to be studying there, you will need to prove you have sufficient funds to pay for the school up-front and also to live there (accommodation and living expenses). Without that, you won't get a student visa.