I use Sew What software for all my resizing- merging- applique overlapping-color changing ect , Any digitizing I have Hatch 2 and it's the go-to for any design work or stitch change- monogramming or it will do any creation or modification that's required for embroidery
Hatch is a big outlay but worth every penny, if you want to purchase wait for the discount about 4 times a year and save about $400