I usually only use the RAWs, but sometimes I import both into LR - I have 'Treat JPEG files next to raw files as seperate photos' checked.
I've just checked a folder that I imported this way.
The JPGs just get imported in LR - though the profile is Adobe Color - so an Acros JPG appears as a mono image even though the Profile is Adobe Color
On a colour image switching between teh two the Colour Profile remians as Adobe Color but there is sdefinitely a difference in colours between the JPG and RAW - if I set the RAW color profile to a Camera Simulation then the colours appear the same as the JPG taken with that profile.
A JPG from the camera is a fixed profile so Adobe will only give you Color/Monochrome options,
Does that make sense?
There is an option in the Preferences > Presets to change the Raw Default - Global Profile - I've never changed this
But I do have a Fuji Import Profile - my version of the Adobe Default Profile with sharpening reduced to zero - I have set this up so that Fuji RAWS have this applied and other cameras still have the Adobe Default. Set Override Global Setting for Specific Camera check to enable this.
View attachment 413166
I'm using Lightroom Classic BTW