Changing/removing the loading screen?

Is there a way to change the loading screen to the Half Life 2 and episodes one? As in when you progress in a level, it doesn’t show the loading screen with the ‘G’

Replace materials/VGUI/loading-logo.vtf.
That should do the trick.

There are several ways you can make vtf images: there are plugins for Photoshop and Paint Shop as well as an easy to use program called VTFEdit.

in your server.cfg
sv_loadingurl “http://yourwebsite.domain/
then you can create custom loadingscreens.