Okay, I made some incremental progress. After seeing that my personal Apple ID had the same issue and could not log in with username/password, but could login using Touch ID I tried logging into my laptop using my dev Apple ID and then signing into to App Store Connect, but that failed. (When I refer to Touch ID login I'm referring to the larger Touch ID window, not the one that just fills in the password because that fails). So then I decided to go buy another MacBook and set it up using my dev Apple ID. Then when I went to appstoreconnect.apple.com I was able to sign in using Touch ID. It's only a temporary solution because I don't want to spend $2k just to be able to manage my apps, so I do eventually want to return the laptop.
Something in the 2FA backend seems to have changed because I've used separate Apple IDs for personal and dev work for 14 years with no issues. If you search online you only see App Developers reporting the issue because I think we're more likely to use multiple Apple IDs in order to separate personal and business purchases for tax purposes. But developers and support techs at Apple never see this because they probably just use one Apple ID.
If you need to take the drastic step of buying another MacBook to access your dev account, Best Buy, has a good sale on M1 Macs and if you get TotalTech, which includes AppleCare, it extends your return window to 60 days.
Topic:
App Store Distribution & Marketing
SubTopic:
App Store Connect
Tags: