To make this "cracked top" feature as useful as possible, are you trying to: (like fuel/tyres)? Improve visibility in VR or on a single screen? Focus on rivals for better pit strategies? My RACELAB overlays (download)
Uncheck "Full Screen" and "Border" in your game's graphics settings. This enables Windowed Borderless mode, which allows overlays to sit cleanly on top without being cut off.
This guide focuses on the aspect—referring either to the Top/Overlay Layer of the HUD or the Server Topology management.