It seems most people believe the colours are not too far away. I’ve been having a look into the R8 a bit more, it’s more expensive but tbh the price isn't really a concern. Although given how much more powerful the R8 is, it could potentially be a light weight replacement for my Lumix S5. Canons RF lens range has much expanded since I had the RP, an RF 24mm f1.8 and 50mm f1.8 would probably do most of what I want.
I agree that the R8 is superior to the RP though it shares the weakness in battery life. But I have the RP and also an R. I don't need to be buying more camera bodies right now.
I have looked at the Lumix S5 in the past and liked what I saw. I rented one for a few days a year or two ago along with a Sigma f/2.8 standard zoom (28-70mm?) . Other than the DFD wobble in continuous autofocus, it performed well. And the L lens mount has been filling out nicely. What I liked in particular, was that there were two lens manufacturers (Sigma and Panasonic) to choose from. I am particularly envious of the L mount 20-60mm zoom lens. What a great focal range!
I currently own Lumix M4/3 gear (two GH5S units) for theater and events, so the S5 would be a really good match. But the cost and inconvenience of switching is just too much.
If you like primes and a 24mm and 50mm fit your style of shooting, then the R8. RF 24mm and RF 50mm are a great setup.
As you were making your post, I was just making notes for myself on what it would take to make my RP my main travel and general purpose camera (versus a M4/3 camera). I mainly adapt EF lenses and my favorites right now, ironically, are my EF 24mm f/2.8 IS and EF 50mm f/1.4. The RF 24-105mm STM zoom would be very practical, but I have always enjoyed shooting with primes. I have travelled to both China and Japan in the past with a Canon 5D and EF28mm and EF50mm. And I didn't use the 50mm that much in those days (I have grown to like the 50mm focal length more in recent years).
And my second thought is that I accumulated some adapters from various 35mm camera mounts the last time I had an RP (Canon FD, Leica M39, Konica AR and Nikon F). That gives me many alternatives to the EF 50mm (about five as I recall). But it also allows me to look at adding a compact moderate telephoto such as an FD100mm or Konica 135mm. When I am shooting for fun, manual focus with the RP's focus peaking is actually nice.
Good luck with your R8 combo!