I have recently switched form using Seven admin theme to Claro as I prepare to update to Drupal 10.
One thing I have noticed, is that when logged in on the front end the icon sizes do not scale well with my custom theme.
I am using rem's and scaling my content using media queries, so that type looks bigger on a larger screen.
Having a quick look I am able to fix this issue by simply swapping out references to rem with ems for the icon sizes including width and height