Here’s a trick I did for the wrap shirts. Instead of the bias tape the magazine instructs us to use for hiding the collar seam, I used a satin ribbon, wide enough to cover the seam allowance.
After the color has been sewn (serged) in place, iron the seam allowance toward the back of the shirt and stitch it downward, while also continuing the front diagonal hems of the wrap parts.
Place the ribbon over the collar seam allowance and stitch it in place with one seam on each side of the ribbon.
Then I have noticed Old Navy uses this method for many t-shirts and mens wear, they even choose the ribbons on purpose in contrasting colors.