I don't think this is a motor power issue.
I use a 160 Nm BBSHD on a cargo bike to get up 16% grades, complete with a load of groceries or gravel bags for my back yard. I don't have issues with the motor having more than enough power to let me pedal up easy if I want to (usually I try and work for it and get some exercise, but I need a break too sometimes and want the bike to take over). I have my bike set up to output about 1000w on PAS9 pedal assist, and if need be, I can instead use the throttle and pour on roughly the full 1750w (peak output goes down as the battery drains). Plus, I have built BBSHD bikes starting in 2018 and have consistently had the same results with the power/effort issue.
So... considering your motor is beefier than the BBSHD (able to handle sustained output for longer thanks to its much larger stator etc.) and has the same torque output on paper at least, I have to wonder if what we are really talking about here is not the motor's problem at all. I'd think we are taking more about gearing the bike. Or using the gears properly.
Going up a steep hill with a cargo load, I am going up to maybe 10-13 mph at an extreme on throttle, with a steady pedaling speed in the 8 mph range, and that 8 mph would equate to light effort at worst. Front chainring is a 42T and rear is typically going to be three cogs in from the lowest gear, which is 34T and leaves lower gearing available. My typical preferred cadence is in the range of 70-75.
Also I have used 11s SRAM drivetrains on two of my bikes and can say they work great with a BBSHD and 160 Nm, but you should take care with the rear cassette, for which you have very limited mid-drive-friendly options. I use Sunrace CSMX80 11s which has mostly steel cogs. A Sunrace CSMS7 is 11s pinned-together steel and I use it on a couple of other bikes but it is limited to 42T which is as far as my SRAM derailleurs can go. A much better choice, believe it or not, is a Microshift Advent X 10s with a pinned-together hardened steel cluster, using an 11s chain (Shimano Linkglide chain is the new low-cost kid on the block versus a KMC11e which is more than double the cost)
If you've got a Rohloff on it, I would THINK thats got enough range in it to at least match what you can give yourself with a derailleur.