Thanks a lot for putting your query here. I managed to solve your case by just splitting the circular face of your eye bolt via Right plane. Please see the figure below taken on Onshape:
and the figure below taken on SimScale after import:
and I can mesh it also using tetrahedral automatic on coarse ;):
Not a great mesh though but one can increase the refinement level
So where is the problem?
I think it seems to have problem in importing the circular ring with the face partition and merging with the lower part you have. I managed to import only the circular ring without cutout in to SimScale easily but with face cutout from the above partition and lower solid partition doesn’t seems to work here. Sometimes, visually the parts looks good in CAD tools but due to some missing partitioning they don’t remain as it is after import. May be there are some weird NURBS playing a bad role here.
I hope this helps. If you have any question/s, feel free to ask.