i'm finding the lack of subtlety the real problem, i get the 'analog' aspect, but it's analog in a cheap saw-wave kind of way
I get that. It's sort of a "Land of the Lost" kind of thing. The BMS makes a very bold musical statement. It's no Prophet 5, let's put it that way...a pretty blunt instrument. And I fully agree that it does not and will not sound like an '80s synth bass. I have found no bass effect that does.
But, sadly, it's head and shoulders above any other synth I have tried, although people claim the discontinued Akai deep impact is as good or better. In my experience, the digital synth pedals (the Bass Synth Wah, the SYB-5, and similar), had nothing I could use at all.
As has been said, you could lower the square wave volume and the resonance sliders, that would be the primary way to tame the tone a little. And, FWIW, I don't recommend "diming" all of the volume sliders - play around with them and see if you can arrive upon something that works better. It is truly obnoxious sounding if you just slide all of those up to the top.
Directly addressing your point, some of the synth patches I have heard out of the Chunk Systems Octavius Squeezer have sounded a little more refined than the BMS...plus, that pedal is also an octaver, a fuzz, and an envelope filter. But it is brutally expensive, and some say, brutally complex.