Monoprice Voxel take 2: with more test prints

first off, thanks for everyone and their suggestions, and apologies for not responding back, was having issues with my personal lemmy instance.

I took everyone's advice and have gone test print crazy. I will attach the pictures to this post. I have tried to understand what I am looking at on my test prints in relation to what is not configured correctly on my printer. it's just not clicking. most of my prints look fine, the surface has good infill and the part looks ok from the outside, like benchie. but underneath, it looks like I am having either adhesion issues, bridging problems and support problems as well. but adjusting setting as suggested in here and here did not really improve anything, and in some cases made the print worse.

I am using the Flashprint slicer that came with the printer. I have tried cura and prusaslice and can't even get a print started on those, even with a raft. I'm sure they are better slicers that what Flashforge makes, but again, something just isn't clicking. any further advice would be greatly appreciated.