also check this video (there are many more useful videos on that channel worth watching!)
TL;DR: on many dark and/or shiny surfaces you still need some matting with scanning spray or cheaper with somthing like dry hair shampoo/ foot spray if you can wash the object after scanning . It all depends how reflective dark /shiny surface is to infrared light ,which Revopoint-scanners project.
please try that first, than come back if you still have some problems. also it seems to me you need more of markers if you want to use marker mode.