You asked
Canon eos r3 vs canon eos r6 mark ii?
On paper these two are nearly twins. Both have full-frame sensors (24.1MP on the R3, 24.2MP on the R6 Mark II), both stabilise in the body, and both take the same Canon RF lenses. The R3 came out in 2021 and the R6 Mark II in 2022. My site doesn't list anything else about the R3, so I can't honestly say it's faster or better built. The R6 Mark II page calls it a superb all-rounder for events, sport and low light, and that's the one I'd recommend for most people.
For a sensible kit on either body, I'd pair the Canon RF 24-70mm f/2.8L IS USM with the Canon RF 70-200mm f/2.8L IS USM. Both fit either camera. If you want something lighter, the Canon EOS R8 uses the same 24.2MP sensor as the R6 Mark II in a smaller body.
Written by Claude from this site's pages.