Blender imports Scultpris’ .OBJ’s just beautifully, no issue’s whatsover so far.
The other way around though… even with basic primitives… I got “… too many connections to a vertex.”
Do I need to ‘prepare’ the mesh for the export somehow first?
What is your xp with this transition?
remove doubles, n-gons, clean mesh…
or just show it visually, share test scene
The error tells you the problem. You have a vertex connected to too many other vertices. Fins them and edit the mesh to remove them.
Select a vertex with too many connected edges and use Shift+G to select other similar vertices with too many connected edges