No daytime lighting on radio for Radio Info

Make sure your headlights are set to off. If you have autolamp/headlights on, your radio will enable the dimmer/illumination feature which lowers the intensity for nighttime. Let me know if you still can't get the screen brighter. Hope this helps.

Nope - Did not solve the problem.

Well the issue could be your dimmer, BCM or the radio itself. I would recommend taking it to a dealer. It's a 2018, right? Are you still under warranty? A skilled mechanic may be able to solve your problem too. I've heard of the 2010+ Malibu radios having some display problems. You could get a used radio and have the dealer program it to the car. Be sure you know the exact year of the car, the used radio comes out of.