The Handbag Edit

Hello can someone please explain to me how to make more 3d seamlines? Especially what i have to do in order tò make a frenchseam (so double line) that doesnt look so flat, i would like It be more realistic. Ill put some Pic of a jacket im making, as you can see the sewing line on the chest Is that grey ugly-looking line, how can i make It more realistic? Thanks all :+ <img src="https://storagefiles.clo-set.com/public/community/202506/53bd1a7827774dee8b7416f19ba27260/images/5f5a562f002c4c4dad072d0da64c59ff1000036816.png" alt="5f5a562f002c4c4dad072d0da64c59ff" class="custom-image original-size" data-id="5f5a562f002c4c4dad072d0da64c59ff" data-width="624" data-height="883">

Seamlines more realistic?

Can anyone share more detailed info about the fabric preset settings in marvelous designer.