Need help A.S.A.P for booling Meshes together - Printing is tomorrow

Dear Communtiy,

please help me to bool these meshes together to get a printable shoe sole. Yet I was not able to bool them together on my own.

If you can help me with this step please send me how to do it or even the fixed file.

It is about this shoe sole:
links mesh.3dm (18.7 MB)

Thank you so so much if you can help me!!

The latticed middle part has some non-manifold edges. You should fix these first…

I eliminated them by stitching the two vertices of each non-manifold edge.

Check reveals your mesh has 1226 pars of faces that intersect each other. The thin worm like meshes under the sole also seem to have a lot of self intersections.

Shrinkwrap in Rhino 8 WIP solves all your problems very quickly:

What printer are you going to use for this?