Screen Brightness reverts after using some applications

[Aravisian]

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Unable to launch MS Flight SImulator X: Steam Edition on Linux

Nvidia dropped support for your graphics card and its last working driver (340) back in 2019. Your issue likely is a graphics issue and you need the 340 drivers. So... You will need to add the legacy-drivers repository: And install the 340 driver.

...In regards to your graphics card drivers.