I've owned the 35A and now own the RF35.
They aren't alike.
The 35A has something special to the image quality. It's got phenomenal sharpness and rendering. But it's huge in comparison.
The RF35 has great image quality, but not like the Art. But it's so small and wonderful to work with. It does everything very well.
I got rid of my old 35A because the autofocus was a nightmare on DSLRs (I've since had great luck with the 50A and 85A).
When I got my EOS R and realized AF micro-adjustment was a thing of the past, I wanted a 35mm again and began comparing the two, just like you.
I spent a lot of time deciding between the two. In the end, I wanted a small lens and I am happy with the decision I made. The RF35 is a great all round lens; light, great IQ, great in low light, IS, etc...
If image quality and look are your first priority, the 35A is for you.
If size is a consideration, you just cannot beat the RF35. The 35A falls into what I think of a 'working size'. I don't like taking out lenses that size unless I'm getting paid.
I don't miss the light gathering of the f1.4 vs the 1.8 - it's a trivial difference. The bokeh at 1.4 is far superior however.
If the two cost the same, I'd have had a harder time deciding, but the RF is 2/3 the price in Canada. Easy choice given my intended use of the lens.