If I were to do the hairstyle shown in your image I would use the procedural hair to cover the entire head as it makes it easier to close gaps. Here’s a link to the Steam community homepage.
How can I change my hair on Vroid?
At the time of creating this application, vROID did not include features to add hair presets to existing hair. If you feel that there aren’t enough points to cover the distance (or even too much), you can add more by going to the guide parameters and changing the elevation. If vROID displays an error message after merging, something went wrong and the target hair preset needs to be removed manually.
How do I import hair textures into Vroid?
Um, I don’t know about you, but I usually just go to the app itself, head to hair and then to texture, choose the default image for the texture and import my hair textures there;;.