Hi @a-non-e-moose and thanks for your efforts. Let's jump in Discord or any other way to DM. It won't be very easy to communicate in detail in comments.
Anyways, the SC team was kind enough to reenable the metadata feature for a few days. That's why we're now able to log in again. At least we know the culprit of the problem though. So in a day or two when they disable it again, I can let you know so you can check it out again if I haven't found a fix in the meantime, if that's fine with you. Thank you.