The 'Q' doesn't really do anything more than put a crop line on the file - if you are using Lightroom it will crop the image when you click the edit icon. It is not really doing any in camera cropping but putting, if you like, a 'trim' line on the file. The Sony RX1RMKII has two choice but both require using JPG files...Fuji uses an "in camera" crop as opposed to a crop in post processing.
In the case of Sony - The smart teleconverter (from Sony's detailed specs): When Sony uses the term Smart, they mean an optical crop of the sensor, with no in-camera upscale, so the image is less MP than full 35mm. Given the size and MP of the sensor the quality is excellent.
When Sony says Clear Image, that means in-camera crop, and in-camera upscale back to full sensor MP.
I have used the Leica Q extensively and it is a post processing crop as opposed to an in camera crop...which allows Leica to use DNG files. It is also dependent on using Lightroom which is provided with the camera.
Something I would like is, to be able use the X100F TC in (slow burst) drive mode as opposed to single shot mode...there is likely a reason that is not possible.
I hope that makes sense.