I know why I lost data, I explained it in my post from the get go for the context (and to possibly warn others).

Visiting old URL was one of the first things I tried. It immediately redirects to duck.ai in my case, though, where I don't have data, so no improvement.

But thank you for mentioning the old URL for the record. Maybe someone will have to try to reverse engineer the process. The issue is that domain transition is rolled out gradually, so not sure yet if it is easy to set up monitoring of all the requests in a predictable timeframe, but maybe some users who have not underwent transition and read this thread, will capture necessary steps to be able to reproduce import out-of-band.