You can build some stealthy fast bikes, either from specialized ebike frames, or just ordinary black frames so the wiring blends in.
Here's my current dream recipe for a street bike..
A pair of bafang G310's could hide fairly well behind a disc brake and tall rear gear cluster + a fat tubed front fork on a mountain bike. Run the front one at 500w and the rear at 800w peak and you'll have something that'll blow a stromer out of the water and look nice while it's doing it. Paint the torque arms and their hardware black. Use a tiny eggrider display and a battery backpack. Nobody will know it's electric till they get a good look or listen up close.
Of course, you want the fast winding on both and an appropriate voltage to hit 33mph.
What i'd do for an offroad build is take something like a GNG drive and strip off the secondary reduction and run the motor straight to a rear disc sprocket, mount it to the rear set tube ( custom hardware required, but not hard to find most of the pieces ) and hide the motor and chain behind some panniers. Use a black frame, black panniers, and black chain. Throw a FOC controller on for noise reduction.
Gear it to do 30mph on as high of volts as you can go, because you will want more torque due to the single speed reduction. It will clobber most hills, but not all. If you want to climb monster hills, gear for 20mph or lower. You'll have so much extra torque on tap that extra gear ratios won't be necessary at all, unless you must absolutely climb that 1 mile long 20% grade
Both of these recipes give you a stealthier and faster experience for less $. They just require elbow grease. Big names still haven't figured out how to build excellent stuff - although i'll admit that some of the built in mid drives are pretty nice! it's just that when they break, they tend to not be fun or inexpensive to fix because mid drives do not have standardized parts and there are a lot of them..