Two additonal notes:

I have rim brakes on small 20" wheels, so I try to avoid long continuous braking, it heats the rims and can pop spokes due to expansion. So a particularly steep hill here that I use for shorter workouts, I often walk down that hill, both to save the rims, and it gives my front thigh muscles a workout I don't get with biking. I did a lot of this before hiking the grand canyon decades ago, the walk down is, believe it or not, worse than the hike up, as you are using muscles you normally do not. I rocketed back up in half the time, also helped by dual cross-country-length poles, so my arms taking a lot of the load too. As far as that steep hill here, I can't bike it up unless I am in great shape, I climb on the bike for the lower half, and currently need to walk up the upper half, that alone is a workout.

There is (or used to be) a road west of Yosemite leading to the park, which has an "old" section and "new" section in parallel. The new is not too bad, longer path, the old is something like continuous 20% grade for one or more miles, pretty straight, it's quite a workout for both drivetrains up, and brakes down, as well as drivetrain if you are descending in a low gear (which I did). If the carmakers didn't have bench tests and dyno tests for both, I'd say they should go there for testing.