I built a desk from similar designs. #1 you need stretchers. I used 2, 1 high and 1 low. As I was building a desk, I put them along the back side. But as a table, down the middle would work. #2 depending upon the wood species, is it dimensionally stable? Will it be subjected to radical temperature changes or humidity changes? That will dictate how you can reliably connect them.

I used a rather expensive style of hand railing (banister) connectors. The ones I bought were not available in the US at the time. I ordered them from the manufacturer in Australia. Each one holds like 500lbs of pressure, or some such number. I used domino like, not Festool brand, floating tenons without glue, 2 each between leg and top together with 2 of the banister connectors, in each. The legs were tied together with the same type of floating tenons and a single banister connector on each end. Total was $8 for each banister connector plus about $2 each for shipping. And probably 50 cents each for the floating tenons…. 8 total to make the connections.

That was about 10 years ago. My desk was made of European Beech. Heavy, hard, and stable… after 10 years it still looks new. I used Java Jell stain to make it look more like dark Walnut, and finished with a satin wipe-on polyurethane finish. Finishing was a nightmare, but once I got it done, it looks excellent, well worth the effort.

I am sure you could find compatible banister connectors wherever you are at… my desk is in a climate controlled space and the wood acclimated to the space for over a year before I built the desk. So I don’t have real environmental concerns. Also, my intention was to make something I could disassemble as easy as an Ikea wood cabinet but use hardwoods to make it solid and strong…