I also notice that there is no link for the 1.9.10-2 Windows latest driver download on the Montage page or the download.yamaha.com page for the drivers. ( https://usa.yamaha.com/support/updates/index.html?c=music_production&k=montage )

Steinberg does provide a link for the driver:

https://www.steinberg.net/en/support/downloads_hardware/yamaha_steinberg_usb_driver.html

However - the lack of a link from Yamaha (Montage pages) does beg for the OP's question if there was a reason beyond a website error ("oopsie") why the driver is not available from Yamaha's Montage pages.

Note that you can find the 1.9.10-2 driver on Yamaha pages other than Montage (pro audio pages):

http://www.yamahaproaudio.com/global/en/downloads/firmware_software/yamaha_steinberg_usb_driver/

Both the Steinberg page and Yamaha Pro-Audio pages provide the same file:

Filesize: 6,016,708 Filename: YSUSB_V1910-2_Win.zip