@RavenLuni I would want to listen to samples of the bass parts specifically, but an idea that comes to mind is:

A bass track sounds smoothest when it's primarily composed of sine waves, but it'll sound "muddy" if too many notes / too much detail is added (and combining two bass parts functionally does the same thing). My advice would be to consider applying a sawtooth or square-wave transform to one bass part, in order to add higher-frequency overtones without altering the fundamental frequency.