As long as you have a 4 year university degree you can apply for and get sponsorship from a company if they are willing to do the paperwork for a work visa, and

As long as you have a 4 year university degree you can apply for and get sponsorship from a company if they are willing to do the paperwork for a work visa, and just renew as required. Knowing Japanese helps a lot, but some tech companies hire English speakers - possibly because most of the employees are foreigners anyways. You can apply directly to companies if you can manage to track down their career pages (and read it if no English version), no prior connections required. However, it’ll be hit or miss as to whether they will sponsor you, and a big question mark if American during this COVID crisis.