Seeking tax info on working remotely

I am an American married to a Japanese citizen. I am a long-term resident of Japan (19years) . I recently have been offered part-time remote work through a US based company. I currently have my own company in Japan and pay only Japanese taxes and file tax exemption for US taxes. How do I go about not having to pay double taxes? Do I ask the US company to pay me with no deductions? Any advice or links you can you provide us greatly appreciated.
Two accountants and one lawyer I have asked are clueless.

If you file a tax exemption for the US IRS, if the US company makes deductions you should be able to claim a refund under that same tax exemption system at the end of the year.

Many counties tax on the basis of world-wide income like Japan, and knowing where you are tax resident is an important part of that and double taxation treaties (including tie-break rules). Not sure why this case should be any different to your other income and the way you have been treating it.