I can't help with the Windows 10 issue, but you can connect to calibre with KOReader.
The KOReader OPDS function works well with the calibre Content Server. There is also a
calibre Wireless Connection function that lets you wirelessly have a device in calibre, much like a USB connection. Even if you only used KOReader to provide ebooks for the stock Kobo readers, it might serve your needs.
Luck;
Ken