I am of the opinion (many may disagree) that the fretless tone (certainly the tone I was after) comes from the instrument, the amplification messes with that tone. Unlike most other folk I buy my basses based on their tone unplugged, even electric basses (I mostly play acoustic/piezo basses), and I was always dissatisfied with their amplified sound because I just wanted the tone of the unplugged instrument but louder. That’s why after the best part of forty years being dissatisfied with amps it took me all of two minutes to decide on a powered speaker. I plugged my RA Mouse into the QSC, played about five notes and got my wallet out, it was exactly what I’d been after for years. It kind of unlocks the genuine sound of the instrument. I found myself always battling the controls of a trad amp to find a tone that was essentially unavailable due to the colouring inherent in the amplifier. I think people struggle to find a tone they like because they have no idea of what the instrument sounds like either un-amplified or amplified without colour (i.e FRFR) so they are seeking an theoretical artificial sound without knowing how the bass sounds fundamentally. All the eq on a bass amp set to the mid-point isn’t the tone from which to build a sound because it’s already coloured so you are probably already working with a disparity between the tone of the instrument and the colour of the amp.