How do I change the color of when hover over a sidebar item?

How do I change the color of when hover over a sidebar item?

You have to update those variables:

$sidebar-dark-nav-link-hover-color:       $white !default;
$sidebar-dark-nav-link-hover-bg:          theme-color("primary") !default;
$sidebar-dark-nav-link-hover-icon-color:  $white !default;