What @Lozz196 says. I've only had limited experience with Mark Bass, but there is an inherent warmth/dullness (according to your take on it) built in. It really isn't down to it being lightweight, as there is a world of difference between many of the lightweight brands. So many on here love the Tonehammer. Me, I couldn't get a decent sound out of it!
Try out as many as you can (yes, I know, not the easiest thing to do even without lockdown) and have some fun doing it!