I’m stuck as well and have sent four separate requests with no answers since January — initial request was January 19th (ticket 338181). I need to update my tax info (which should be tax exempt, I realized) and don’t want to request a payout until I fix it. It’s been super frustrating!
Normally, if you request a payout and your tax information is out of date, you'll be prompted to update it before Itch.io continues with the payout. If there is no payout request, itch.io doesn't usually let you update the tax information, because it costs money and it might be out of date again before you qualify for a payout.