No, I don’t think you can manually assign an elevation to an entity. That would require a Ruby code snippet. The first thing to do is import the DWG file into Sketchup which would require Sketchup Pro. I know there are plugins for importing dxf files but can’t seem to find any for dwg.
There are several AutoLisp files you can use in AutoCAD [and compatible apps], which make elevated 3d-points based on their 2d-text values.
BUT it requires some ability to filter [purge] a copy of your DWG to have just the text [for the points] in it, before processing…
Then you’ll have a DWG with 3d-points.
Now you can import that DWG into SketchUp as a 3d-point-cloud…
However, it would be best to get a DWG with real elevations for those points.
Your surveyor should have provided one [if asked!]…
Again, there are then SketchUp scripts available to process those [already elevated] 3d-points into a surface mesh.
Search at SketchUp Plugins | PluginStore | SketchUcation…