Look, let's talk bass distortion
There are all sorts of different approaches you can take here.
You could go for the cheesy digital approach, and spend 80 dollars on a pedal that will sound, well, like an 80 dollar pedal. For instance, the go to bass distortion is the Boss Bass Overdrive. Not the worst thing out there, but certainly not the best. EHX makes wonderful fuzz pedals and what not, if you get a Sovtek Muff (the black one) you'll find it has a higher register than the typical Big Muff.
I like to go a different route.
Try the Megalith Fuzz pedal. OR if you want to search for this guy, try getting your hands on the Sanford and Sonny BLUE BEARD FUZZ. This fuzz pedal sounds like "Cliff Burton playing through a Model T that has just burst into flames"