I am on the verge of buying myself something more up-to-date, have upcoming events where I could benefit from a new camera. My main camera at the moment is a Canon 6D and I'm taking advantage of many detail settings on cameras, enjoy Magic Lantern.
For me, depending on what the second-hand market offers me at the best value for money, I am currently considering buying:
-Sony A7 III with Sigma MC11, Canon 5D Mark IV, Canon R
-Canon RP, when I come to a really quite cheap offer
In short, among these, the A7III is the most advanced camera in the price range (despite adaptation), the 5D4 is the most reliable camera, the R is an intermediate.
I'm very convinced of the 5D4, it's the DSLR in the Canon segment for me, I could well justify the surcharge, but still the camera is too similar to my 6D with Magic Lantern, after all I've been getting along with the 6D for years.
I think the A7 III is complicated, hard, cumbersome to adjust, with the adaptation you involve a third manufacturer and you have to expect quirks, but this camera really offers the advantages of an EVIL, offers the largest set of functions in a quite pleasant way, once the camera is personalized.
Again, the canon R for me offers a compromise in between. The RP (with weak batteries, old sensor tech, restrictions) falls short of providing a significant leap in such a way that I'd consider to put money in a 6D2 instead.
What I actually look at are the R5 and R6. With the R5 I'm not even bothering to consider spending that much money. And I think the R6 is still too expensive on the market. Here I directly compare the R6 with the Sony A7 III, which is roughly equivalent for me, the A7 III just more of like the nerd which is better but with whom nobody wants to be friends.