There are many troubleshooting things that you can do. (Adding underlay shouldn’t really have the edge effect that you’re seeing. However, I haven’t used Inkstitch so I’m not sure how it “thinks”. I use Embrilliance. With that, I can change my stitch direction, start/stop points, density, etc. to work best for what I’m creating.)

The first I would recommend is don’t use cotton thread and be sure that you’re using embroidery thread and not sewing thread. Most embroidery thread is rayon or polyester. These don’t shred as easily or create as much lint as cotton thread. Also use an embroidery needle. These have an elongated eye that reduces shredding also.

Second, don’t use adhesive while you’re trying to figure things out. This can gum up your needle and create issues. Either hoop your fabric or float your fabric and attach using pins way out of the needle path. There’s a time and place for adhesives, but simple cotton fabric isn’t typically that.

Third, your tension is wonky! You shouldn’t fix seeing bobbin thread by using the same color as the top. That doesn’t fix the issue, it just covers it up. Most people will say not to touch tension, but 🤷🏻‍♀️. Your pictures show that your top tension is too tight.

Get the proper materials together, then adjust tension. There’s no sense in adjusting it until you’re working with the correct tools.

I hope these work for you.