That's not how the the assist levels work on the Ride1Up bikes in current generations. The assist is based on power instead of speed. Kevin of Ride1Up talked about that change in an interview earlier this year.
Also, you don't have to use 9 assist levels - that's another option to set the range. And then you can adjust each one's power percentage. Great stuff. The problem with some bikes, like the Aventon Level, and I'll even put previous generations of Core-5 in that group, is that they have too much assist on level 1. That's not good for me - I want minimal assist in level 1 as to use more muscle power while still riding at a moderate speed. If you just want to ghost pedal around and aren't interested in exercise, then those other bikes might be just fine.