Hello Daniel! Here is an explanation I found online and hope that it helps:
One possible explanation is that the default settings for gamma and color management may have changed with the update to the new version of Premiere. This could result in a brighter, more washed-out look.
You can try adjusting the gamma and color settings in Premiere to improve the look of the footage. The steps can vary depending on the version of Premiere you are using, but typically you can find these settings under the “Project” settings menu. Look for the “Color Management” and “Gamma” settings, and play around with changing the default values until you find a look that you prefer.
Another possibility is that the new version of Premiere is using a different rendering engine or different encoding settings than the old version. If the two systems are not set up identically, there could be differences in the way the footage is being rendered. One way to troubleshoot this is to compare the encoding settings between the two systems and make sure they are the same.
If none of these solutions work, you may need to contact Adobe support for further assistance. Good luck!