Final Cut Log Footage

The application automatically applies the Apple Log LUT to the clip. If you don't want to use the LUT select all the imported clips and in the Info Settings inspector switch Camera LUT to None.

When you say a "bit edited" do you mean the colour is not the same? When you import the iPhone 15 footage, FCP tries to be helpful and applies an Apple Camera LUT to the clips to move them to the correct colour space. If you don't want that then select the clip in the browser then under the inspector select the "I". Make sure you have "General" or "Extended" selected and you'll see Camera LUT. Change that to None or some custom LUT. After that you should have the raw image to work with.

I think starting with FCP 10.6.6 there was automatic color conform, which should normally handle most situations with iPhone Apple Log HDR or HLG material. See this Apple documentation: Use automatic color management and Color Conform in Final Cut Pro for Mac - Apple Support

On my iPhone 15 Pro I just tested ProRes recording in the HDR, SDR and Log formats, then imported those clips to an FCP 10.7.1 SDR and HDR library, and all six combinations looked OK. FCP Settings>General>HDR:Automatic Color Conform was enabled.