Getting better topology using Zremesher in Zbrush 2019

Paint on your model with the standard brush, use polygroups in the pointy areas to keep corners sharp. Use polygroup from paint to define groups and then  tessimate to even out the polygons. Polish by features or groups a couple of times, then uncrease all to get rid of the mini creases on the model. Then use "create pg" to crease polygroup borders. The next step is "mirror and weld" to get rid of the warping on the center line. You will get rid of the tiny polygroups by Ctrl-Shift clicking on the line between two polygroups.

Once your model is celaned up, you can remesh it with zremesh. you will do it a couple of times, repeating uncreasing and creasing pg again to get better results.