Latitude 3480 Poor Video Playback Resolution

Overall graphics are mostly fine for day-to-day usage or viewing photos, for example. It also works fine to watch videos online on youtube or netflix.

However, when playing videos that are saved on my computer or for video calls such as skype or hangouts, the quality drops significantly. See screenshot below to understand it better: 

First, a print from the video on youtube. Colors, quality and resolution are fine.

Now, the same video, but after I downloaded the video (in high-def) to my computer. Colors are weirdly bright and resolution is significantly worse.
(Note: To make sure that it wasn't a download issue, I copied this exact file to a pendrive and played it on another computer and the quality was fine.) 

The exact same thing happens when I'm on video calls, where the image is poor like the one on the second  screenshot (and I've done several tests using different devices for these calls).

I tried to update the video driver, by downloading Intel UHD Graphics 600 and P600 series Legacy Driver from the Dell Support Page, but when I try to install it, I get a message that the system does not meet the minimum requirements to install it (which is f'd up since I downloaded it from the Dell page for this specific model!!).

Anyways... Any ideas on how to solve this issue?