I have had no success at low temperature roasting, I have gone through a number of hacked popcorn popper coffee roasters. This requires some tweaking to get the temperature high enough to get a good roast. As a result, I have wasted a few pounds of beans on “low’n’slow” roasts. If you leave the beans in long enough, they will turn dark. But they never develop robust coffee flavor.
A green bean has no flavor. Lots of caffeine, but no flavor. It is the roasting process which converts bean constituents into yummy coffee-flavored chemicals.
The Maillard Reaction is a specific reaction between amino acids (building blocks of protein) and reducing sugars. It produces specific chemicals like 3-deoxyhexosulose. These products do not provide coffee flavors. Which is good because otherwise your bread and French fries would taste like coffee.
If you roast beans at Maillard temperatures, you will have brown beans that taste like dark toast. But we don’t drink coffee because it tastes like toast. We drink it because it tastes like coffee.
I have given up on popcorn popper roasters. They don’t stand up to proper coffee roasting temperatures. I have switched to a BBQ rotisserie basket. With an eye on the thermometer, it does a very good job and leaves the stinky smoke outside.