Just a heads up that object-fit: Cover; is no longer working behaving strangely in the latest Chrome update.(Version 92.0.4515.107 (Official Build) (64-bit), I'm not sure if it's a bug or not!
I've literally just spent an hour trying to figure out if any files had changed whilst developing a website as the slider which uses that CSS rule was no longer working as it should, so I tried on another PC with Chrome and it was working perfect until I updated through the settings. I've submitted a bug report just in-case.
Edit: Although something has definitely changed in the new update with the CSS rules, e.g: in a bootstrap 4.6 carousel, I was forced to use some extra CSS rules so it did not behave like it did in IE. Basically I had a full width carousel, with video as the first slide and a couple of images with buttons etc, which worked perfectly across all browsers apart from IE, adding the below code fixed it.
.bg-slider .carousel-item img{
width:100vw !important;
height:475px;
object-fit: cover;
background-position: center center;
}
.bg-slider .carousel-item video{
width:100vw !important;
height:475px;
object-fit: cover;
background-position: center center;
}