The Octoprint host doesn’t see anything at all when the USB cable is plugged in.
My guess at this point is that your attempt at flashing the bootloader corrupted the bootloader.
You’ll need to work on reflashing the bootloader if you are going to recover this board.
There’s a thread here in the V1E forums about how to do this:
Edit to add: Since you previously tried to flash a bootloader, you might want to double check that you returned all the jumpers on your SKR board to the proper position afterwards. Failing to do so would also leave you in a no-boot scenario.
That’s one reason I suggested you share a picture of your setup in the replies up above.