If the firmware version on the Oasis is close enough to the firmware version on the new kindle, you can copy the book.sdr folder and all its contents to the new kindle.
I would try this as an experiment. rename the book.sdr on the new kindle and copy over from your computer for 1 azw book and one KFX book. Only try this with non-amazon books. It sounds like your amazon books are already OK.
Longer term, you need to hope someone will write companion utilities for jhowell's KRDS reading utility that can write to kindle reader data store files. jhowell has already said he has no plans to do so.
https://www.mobileread.com/forums/sh...d.php?t=322172