I've been messing around with Autodesk Fusion 360 as an alternative to Rhino for modeling software. I've been very impressed with the intuitive documentation interface, and see a lot of potential pseudo-parametric modeling. The gold standard for me in that regard is Revit. Of course, my side table project isn't exactly a building, and as a hobbyist, I have to work with the software I can actually access. From what I've seen, Fusion is almost parametric. It's possible to go into the edit history of your model and tweak an operation you did. I can see this working fine for simple things like my side table, but cringe at the headache potential if the model isn't set up correctly for whatever tweak one might want to attempt.

Nevertheless, I committed myself to modeling the side table, and working through some different versions to see if I couldn't resolve the question of how to support it.

I started by getting the base model set up with the dimensions I'd determined. Fusion 360 is a less intuitive modeling environment, so getting this done was an achievement for me. The first version I tried out was the "Mass" within the ribbon. I offset the "mass to one side, a kind of dual-shelf/drawer approach.

Next, I tried different versions of the support as like a "Core" mass. I put it smack dab in the center and even pulled it off the inside wall so it had all 4 sides. That would be a weird kind of drawer, and it's tiptoeing towards being a building...

Version 3 has 2 fins making some cubbys. I do like cubbys, but it still doesn't seem quite right.

I can't count the number of times I've come back to the original sketch for something after modeling a whole bunch of different alternatives. I'm now 95% sure this is the design I'll use. To keep the "ribbon" as the strongest design feature, I'm going to hold the center rib back from the edge. I might also make this a different type of wood. I think I've got some scrap pine that would work.

Even though I landed on my original idea, going through other versions was still useful: it provides me the reassurance that there's not an obvious better answer out there.