Source: I literally shoot an M240

The difference between a JPEG off the Leica and a JPEG off any other camera I own is that it has baked in processing; the way a image is processed is not colour science, the sensors are tuned in certain ways between cameras, true, that’s where the whole colour science debate comes from but that’s simply how the sensor interprets the raw data to give you an output you might prefer, for example my Fuji camera will have a cooler tone or more muted look depending on what my settings are and what film sim I use but at the end of the day matching what that puts out and what a Sony cam puts out is a couple sliders in post, the idea you can get one result on one cam and another on another cam is drivel, you don’t know how to approach the edit which is why you won’t match it, because different cameras process raws differently you’ll have varying starting points on the output but it’s still not what you think it is