Not having a university degree makes it much more difficult but not impossible. However, if you are hoping to immigrate here, your options are probably as the spouse of a Japanese national or a foreigner with a valid visa, as a “trainee” (working for a Japanese company for very low pay), or self sponsored. The self sponsored route would involve setting up a subsidiary company in Japan, then transferring yourself from the parent company. Given that you’re starting out, that route might be quite challenging.
My advice would be just to come here (when the borders open) as a tourist and do a workation working with your existing clients outside Japan. Before COVID, it was relatively common for freelancers to come to Japan for a 3 month “workation”. You’re not supposed to work on a tourist visa, but since you’re serving clients in your home country and being paid in your home country, it doesn’t really matter.
Short term accommodation is much cheaper than hotels, but also much more expensive than regular housing. If you’re in Tokyo, you’ll need about $4,000 to $5,000/month to live comfortably. You can do it cheaper than that, but there will be quite a few compromises that could affect your ability to serve your clients.
If you’re still thinking about the visa/immigration route, you should just talk to an immigration lawyer in Japan.