On their own merits, most Contax cameras are good. But if you can shoot a Leica instead ? Electronic nightmares.
The Leicas are much better, to me, for making pictures.
The SL2 is a wonderful camera, but may need some renovation at this point.
For me, the R4 - R7 series, without a moment's doubt, are preferable over the R3.
I'm curious about the 'shutter lag' attribution about the R3. I was shooting things like soccer at the time, and recall the 'temporal parallax' of the R4 to be an improvement over the R3, but it's been 25 years so I don't remember the numbers. It was faster, too, than an F1 or F3... it just sounded 'cushier'. At the time, I was working at a largish Leica dealer, and Leica still had great support - there was a lot of data available- but like I said, I don't remember the actual numbers. And nowhere near an M camera.