Consistent brightness from desktop to iOS? (Changing gamma?)

It took a little while for me to notice, but my game is much darker on mobile. I'm looking for ways to get brightness more consistent with what I see on desktop.

The threads I found are either inconclusive or outdated (6+ years ago). I found Color Space in the Player Settings, but that has only two settings, Linear or Gamma. I was hoping for a Gamma slider, like in Unreal Tournament 2004. Is there any way to achieve that in Unity?