Lens Profiles with TIF-files

Hi,

My workflow is mainly hybrid. I.e I shoot medium format film, scan on a flatbed and then process in Lightroom Classic CC. Some of my lenses, like the Pentax 645 45mm, is rather wide and creates somewhat barrel shaped pictures. I would like to apply a lens profile onto the tiff-file to see if that help. From googleing I understand that a good few lenses are withheld from the list of available lenses, the mentioned lens included. I have found some tips here on the forum suggesting to make a copy of the .icp-profile file and then alter CameraRawProfile="True" to CameraRawProfile="False", throughout the file. However that file is not loaded (or ignored) when I restart Ligtroom. I see there is also an index.dat file in the parent folder, but from my judgement it shouldn't be altered.

How can I make Lightroom load the file in question? In other words, how can I gain access to lens profiles for lenses exempt from the list of non-RAW lens profiles?

Kind regards

Erik