The off-the-record approach still works for me without error in Windows 10. No 'deadline expired' messages logged and multiple instances still work. The cache path is empty in the log file, and no cache folders are being created in either the Local or Roaming locations. But I assume that's expected with OffTheRecord cacheing? As I understand it, OffTheRecord is memory based.
I've attached the log file.
RE the named profile strategy:
I found this bug report:
https://github.com/martinrotter/rssguard/issues/1496
Which leads to the following Qt bug report:
https://bugreports.qt.io/browse/QTBUG-129620
The gist is that the very act of creating a named profile on Windows creates an empty directory in APPDATA/Roaming before the correct data path is even able to be set.
It shouldn't be too hard to clean those paths up, but we need to make sure that there are no problems with running multiple instances on any Windows machines if we ever go back to using that approach.