To get the most accurate results, look for LUT packages labeled "Rec.709 to Gamma 2.4" or specific "QuickTime Gamma Compensation" fixes. These are widely available on professional colorist forums and GitHub repositories dedicated to video engineering.
A .cube LUT (Look-Up Table) acts as a mathematical bridge. It adjusts the pixel values of your video to counteract the lifting or crushing of blacks caused by the software. Save the .cube file to a dedicated LUT folder.
Your video looks perfect in your editor but loses contrast once it is rendered through a Qt-based interface. How to Use a Gamma Compensation LUT