You said your computer had a wifi connection problem ... but then you said you'd tried solutions that didn't involve your computer.
I really think you should buy a cheap wifi dongle.
Like this: https://www.amazon.com/Wireless-USB-WiFi-Adapter-PC/dp/B093FT3H7L/
The V850 can do all sizes of negatives.
So you should definitely get the scanner, and do the test yourself. Find a few print/negative pairs, and scan both, and see which give the better results.