How do I separate de JPG version from the RAW version in LRC? Somehow they are piled together and I cannot find any catalog settings to undo this...

What I think you need to do on order to have the RAW and it’s associated JPG appear as two seperate (and independent) images in LrC is:

1. change the catalog setting to treat RAW + JPG pairs as seperate images (for future imports)
2. have LrC forget about the JPG’s where there are currently JPG+RAW pairs
3. re-Import just the JPG’s from the ones that had been paired with RAW files (you may have to disable the “Don’t import suspected duplicates”)

It should be noted that by doing this the RAW files will still have your edits but the re-imported JPG’s will not and after they are in the catalog as seperate images, edits done to one will not be applied automatcially to the other.

I have a blog (https://www.danhartfordphoto.com/blog/2018/7/lr010-lr-classic-how-to-remove-redundant-jpgs ) which addresses a different use case but may contain some useful information.   Obvioulsy in step 2, don’t delete the JPG’s but rather move them to a new folder.

What exactly do you mean with “piled together”? Lightroom Classic has a preference setting to treat JPEGs next to RAW files as separate photos. If you do not check that box, then the JPEGs aren’t really imported, but used as sidecar files for the raw file. That looks like this:

In the Library module, use the Filter Bar, click on Metadata, then set the left-most column to be File Type. Then click on JPG or RAW to switch.