Is there a way to remove the default dashboard templates or at least let the custom ones appear on top?

The default and custom dashboard templates are located in this folder:

Drive:\ibi\WebFOCUS53\worp\worp_html

The name of the template folders must begin with "worp", but it appears that the rest of the folder name can be any alphanumeric characters, I'd stick with a maximum length of 8 characters for the name.

You can delete the default template folders (worp0, worp1, etc.), I would suggest making a backup first.