If you don’t like the bokeh, there are good primes for every system. Bokeh is very subjective, some like it smooth, some swirly, some like onion rings… There’s no definite “right” answer, but each lens can only pick one of those options. I’m sure Canon builds one you’d like.
As for your EOS R, I can’t comment. Never had one, nor felt the need for such a system. But if you were happy with the bokeh on your APS-C 35 f/1.8, perhaps you don’t need the even wider apertures afforded by a full frame camera.