R5 & RF100-500mm - experience adding teleconverter?

I bought the RF2X along with the RF100-500 fully accepting the limitation of the zoom range for the 2X. I like it a lot. For my purposes the 1.4X was not extending enough for my chosen uses.

I wrote how I made that 2X choice and what I thought were the design criteria used by Canon to make the combination of the R5, RF100-500 and the RF2X which you can read here:  https://www.dpreview.com/forums/post/66180309

Since that above post, I have spent many hours waiting for our local Peregrine falcons to fly, taking photos from the close and long distances of the birds standing on the cliffs, with and without the 2X extender on the 100-500. When I compare the images in the computer the 2X extended images at 600-1000mm look a tiny smidge softer and have slightly lower contrast at the adjusted exposure than do the 500mm photos from the native lens. However, the extended images also have more detail as the focal length is increased. In the case of 2X500mm vs 500mm the increased detail is significant.

So, surprise, surprise--increasing the pixel count for the subject can mean significantly greater detail of the subject. Then when you post process the raw images to optimize contrast, color temperature, sharpness and so on and the images from the 2X extender are terrific.

The common statement about extenders and zoom lenses is that extending greater than about 1.4X is not  worth it because of the loss of sharpness. In the case of the R5, RF100-500 and RF2X, my experience is that this is not true.

Don