The ef 35mm f/1.4L II has spectacular IQ on the R5/R6, and it balances as well as (or better than) any of my RF lenses.I spent the day with my RF50 1.2 (indoor kid birthday activities) and was constantly backing up. I suspect a 35 will replace the 50, and the 85 can take up the portrait distance slack.
But, for me, not all EF lenses have good ergonomics with the adapter. For example, I had a very good copy of the ef 70-200mm f/2.8L IS II and sold it because it was too front heavy and the zoom ring just wasn't quite right with the R in portrait orientation. Too clumsy.
Definitely worth grabbing the ef 35mm while they are still available, imo.
I agree with you about 50mm being problematic in typical home-sized rooms for parties and other events.