First, I am an extreme hobbyist. I shoot my kids high school football and basketball games. (Nights and in the gym). I have done IndyCar events, and previously did a fair amount of wildlife. I previously have had the 5d Mk4, 1Dx Mk2, etc. I traded both of my DSLRs to move all mirrorless through a couple of stages. I held onto the 1Dx the longest prior to getting the R6. So I have been shooting with both throughout the past almost year. I personally tend to lean toward the R6 the most but reserve the R5 for just portrait work of family, events, seniors, etc. so I have flexibility to go back and forth. For wildlife, to me it comes down to what glass you have. If you can live without the crop, the R6 is more than capable as it gives you that bump in lower light images. I still fiddle a bit with some of the differences in color contrast with the Rs but HCS not regrets for move I made to mirrorless. While I usually use my R6 for most things, I do like leaning on the pixels of the R5 when I need to. The question I would most certainly have is how long would you plan on keeping your next purchase? I feel very comfortable having made the move to the mirrorless side (and I know I am in a bit of a luxurious situation of being able to acquire both). That being said, if I could pick only one of the two, it would be the R6 without any regrets. If I need more reach, I like to push on the glass if I can versus depending on any crop methods either sensor or software. The other question when it comes to resolution is what do you do with the final product? Don’t need many pixels to generate a nice 8x10 print. Just my ramblings.