When I first got the Helix I was massively unimpressed with the fuzz
However, like in the real world, the fuzzes, especially the arbiter, want to be first in the chain and "see" the guitar pickups
I have found the key is to use the fuzz first in line with the button to switch it on & off also mapped to swap between auto impedance (when fuzz on) and 1m (when fuzz off)
This way you get the right impedance when the fuzz is on and when the fuzz is off you get a normal clean tone with weird no loss of treble
When you use a fuzz with a higher impedance, the tone will be ulta - fizzy and not real world
YMMV