I had an R and loved it, ended up selling my 5D IV and didn’t look back. In fact I bought a second R as a back up body.
Decided to upgrade to the R5, sold one R wi5 plans to use the second R as the backup. Big part of deciding on R5 vs R6 was dropping pixel count with an R6.
After a few weeks with the R5 and seeing what people were saying/posting with the R6 I sold my second R to get an R6 as my second body.
Luckily I make money with my gear so easier to justify and afford the higher end models. That said, if I wasn’t making money with my gear and was trying to decide between the R and R6 I would pick the R6 every time.
The MSRP difference is $700, for that you do lose 10mp but what you get is definitely worth the money.
-Better controls- three dials, a wheel, joystick, more programmable buttons and NO Touch Bar.
-Dual SD card slots
-Industry leading AF. It is FAST, it is ACCURATE, Eye AF is almost fail proof. The AF improvements alone are easily worth at least half or more of the price difference as far as I am concerned.
-IBIS
-While the R made a splash with its low light capabilities, the R6 takes it to a new level. Low light? No problem with getting usable files at ISO 25600
If I had bought the R6 first, I probably would have gotten a second R6 instead of the R5/R6 combo.
Finally, if you buy an R new, understand you are losing at least $500 in value just by opening the box. Used R prices are around $1200 right now. If you are ok buying used, you can certainly save money vs an R6. While I am ok buying used lenses, there are a lot more electronics and things that can go wrong in a body so I tend to stick with new.