Haha the issue you’ll have with the backstory and brand is that lighter roasts are seen as the trendy coffee so they’re often pandering to an audience who in some cases probably care more about the image and backstory than the coffee itself.
You’ll get a lot of mediocre cr*p for the same reason!
The challenge I find is that a lot of roasters don’t list roast degree so you sort of have to just hope that fruity sounding coffee above £30 a kilo is going to be light.
Dark Arts do some good ones and I think offer 100g bags too if you just want a taster.
Ozone have some really great ones.
Curve coffee, although again you’ve got to guess if they’re light roasts based on flavour notes.
Hard Lines also have some lighter roasts too.