@carlbiker - I've not ridden a Bosch, so I can't comment. But I weigh
75 lbs *more* than you, with a weaker 70Nm Shimano motor.
I have chronic L4/L5, L5/S1 sciatica issues too since early 2000s, never got surgery. I've got a very small stripe of dead nerve down the lateral side of my leg but it's very minor. Since yoga body-awareness education and stretching, I've thankfully haven't had many crippling episodes in 20 years. Bad knees...the works. That's why I went e-bike in the first place. 70Nm still seems plenty for me riding solo.
I would take a look at your current settings for motor assist. What mode do you currently use? I'm not familiar with Bosch's eMTB mode but Shimano has ECO/TRAIL/BOOST. You can do a mock-up ride of 52 Nm just by dialing down your assist and see what that's like. Of course your FF bike is 10lbs heavier than an M10 I'm guessing, but at least you'll get a feel for your "minimum acceptable assist" and go from there.
Which begs the question....with all your concern for Nm specs and motor support, why are you shopping for a Rise in the first place? I think the Rise is definitely king for the lightweight emtbs right now and not at all lacking for power *within it's class*, but if power is #1 in what you're after, sounds like your FF bike is the best answer to your needs.