Modding a Behringer SF300 Superfuzz, change fuzz character

So a quick heads in, im a complete noob at this, the most complicated mod i've ever done on a pedal is removing the diodes from a Boss BD-2 a couple of months ago.

i recently acquired a behringer SF300 and while i really love the sound, id love it even more if i could mod it to make the distortion tone ''cleaner'' because playing three-note chords that arent perfect fifths is near impossible (i play 9th chords alot)

How should i even try and approach this? any recs? also couldnt find the specifically schematics of the board anywhere online, maybe im just real stupid at searching for this stuff still lol

again, please keep in mind that im a complete noob. ANY HELP IS WELCOMED AND APPRECIATED