Also try connecting it an external monitor or TV and see if you get the same. That would eliminate the laptop screen. On my laptop, I also had to turn the brightness down.
On laptops, the power settings might also be kicking in to dim the screen? In Windows 10, you can tell it to allow MSFS “High Performance”. Settings > Gaming > Game Mode > Graphic Settings > Choose an app to set preference > then select MSFS - this will disable power settings for that app.
EDIT: I’ll add this too… I’m sure you’ve checked it but I’m going to through it out there. Check the “Night Light” setting in Windows 10. If it’s on, turn it off. On turns off the blue emitting light which makes that “grey” color in the cockpit.