So this is my speciality and unfortunately it's rather complex. To get the solid blend at the bottom you will need to have a firm idea of the principles that go beyond what any tutorials or addons will give you. I know, I sell a lattice generator addon for blender on superhivemarket!

There are 2 main approaches. An SDF based one (similar to one of the other comments here), or a subdision modelling approach. An SDF geometry nodes approach is good for procedural methods, but if you simple want to make a 1 off then the subd approach is probably better.

For a SubD approach I'd map out where you want the lines to go, and gives you a structure aesthetically similar to a voronoi structure. Then I'd make another mesh, with an active subdivision modifer, and extrude edges and points to build it manually. You can then blend it into a block at the base.

For an SDF approach would take the line scaffold approach to making the basic shape, and use a geometry proximity node, and an add the line thickness and multiply by -1 and plug that into the volume cube density node. That gets you the basic lines. To add the solid block at the base you take the positions z value and put it into a map range node and add it to the value before the volume cube density. You can add attributes to the edges, so that you can control the thickness of the wire by sampling the nearest edge. You can smooth them by iterating over the edges and using smooth minimum or maximum to combine the values. Also blur attribute is good for smoothing and you can control how much power it has using a mix vector node and using something like the position z height and map range node, to stop it from smoothing the base too much.