Sorry to hear about this. Please elaborate the issue you are experiencing with Color Key effect. Are you unable to sample Key Color, or is something else not working with the effect? Also, let us know the version of Premiere Pro that you are using.
I apply the Color Key effect to the clip. I sample the color as in the screenshot above and this effect no longer works. I checked old projects where everything worked. Now it doesn't work either. I thought it was a preview issue, but it doesn't remove the color after rendering either. I removed the effect and added it again, but it didn't help either. The last time I used it was on June 19, 2024 and everything worked fine. Maybe it's a matter of the update that took place then?