I don’t know the content embedded in the GoPro file, so I can’t even see alternatives.
I found that Exiftool has several Lightroom plugins. Maybe you can see if one works for you.
The use of Exiftool is by commands, I suppose there will be some command that allows you to generate the camera model label.
Here is an example to change the model of the image scanned with a Noritsu scanner and that previously the camera model did not appear in the EXIF information.
Using the following code ~$exiftool -model=“sam’s camera” ff4204…jpg (ff4204 is the file name of the photograph), the user managed to include the camera model (sam’s camera) in the EXIF data of the file.
With Exiftool GUI, introduce in “Exiftool direct” inside Exiftool GUI the code
-model="sam's camera" filename.mp4
I seem to remember that the file name cannot have hyphens, in separations, only under hyphens.(example: filename_01.mp4)
-, I managed to add a random camera model inside the XMP format (Extensible Metadata Platform).
I don’t know if lightroom can handle this.
Tomorrow I will try to record the procedure to show it to you.
I did the test with a .mp4 file (HEVC), because I don’t have GoPro files.