Although the geometry result's the same, the single boolean of a closed sawtooth profile extruded and intersected with a copy rotated 90 degrees can be less computationally intensive than multiple booleans.

A miniscule sphere centred at the coincident point of adjacent edges and subtracted from the minuend stops fillets from continuing into the adjacent edge. Subtract from both ends of the edge you want to isolate or it'll continue around the entire connected edge anyway. The sphere can be infinitesmal...

Your object has no prospect of being processed into a solid, or even a single manifold mesh, because it's composed of many objects with arbitrary relationships and occluded spaces between them, many outliers, and things like the handrails that are almost impossible to take from scan to model without...

You could Boolean Section a 5mm plate (box) with the base of the object, you'll have upper and lower inner and outer wires/polylines result. Downgrade the section to separate the profiles, draft clone and scale the inner profiles up by 1% or 2% (arbitrary, to prevent degeneration from coincident sur...

There is the interesting commercial IronCAD, which has two kernels, ACIS and Parasolid. I've never even seen it, I don't know how they operate together.

Commercial TurboCAD can do it by downgrading the mesh to individual polygons for each face, applying thickness attribute to all, then Boolean add all. It usually has reversed normals on some proportion of the facets, so those have to be selected separately and be given a negative figure for the thic...

In Australia, there's a company in Dandenong, Victoria called Spee3D, they invented a fast additive metal process with CNC subtractive finishing/post-processing if it's needed. Well-respected, very fast and relatively economical (everything's relative, of course....)

The Mesh workbench Mesh|Cutting|Cross-sections can be used as 2D/2.5D tool paths, but (a) downgrading them makes every segment an Edge, making it pretty intensive, and (b) you need offset for tool compensation. Upgrade each section to a Wire, symmetrical-extrude the wire in Part WB (don't make solid...

You can use the mesh workbench to remove the triangles of the raised text, then to fill the holes they leave. You can produce the replacement text in other workbenches and create a mesh with one of the meshing tools, then use mesh WB (with OpenSCAD for booleans) to add it to the existing mesh body. ...

Select the face you want to offset, use Draft|Trimex, escape with zero extrusion. That creates a face that you can Part|Offset 5mm with fill between face and offset, add that to your original part.