Windows photo viewer is actually the good application :- ). It's color managed (respects sRGB vs others), so people with wide-gamut monitors see their pictures correctly.
'Photos' App (Default in Windows 10 ) is the wrong one, it ignores color profiles and thus shows full monitor gamut regardless of image. So on wide-gamut displays it's over-saturated and contrasted.
16bit jpeg you mean jpg2000 ? I actually learned by accident (never used it) it has 16bit support :- ). But really, for web use, save as jpeg (classic, 8bit one, you can keep PS at 16), with sRGB profile.
But really, something else is going on here.