the “two piece” part is mostly easy. there are two ways to go about it.
one is to use a box maker like Boxes.py and use the two-piece box settings. that makes a “sleeve” style two piece box.
Here’s an example of that style.
the box I made here is actually three partial boxes. the first two are the same box (although in this case I altered the flat edges to be opposite/match up curves). the third box is one that has exterior dimensions being ever so slightly (like a couple hundredths of an inch, IIRC) smaller than the interior dimensions of the second box. you can adjust height to be slightly taller if you want, but by default if it’s the same height as the original box, it will stick out the thickness of the bottom panel. and then you slide the smaller box into the bottom piece of the larger box and it creates a lip so slide the top box over.
i guess the third way (and i’ve done this before, too) is to create the two equal boxes, then create four flat panels that will fit inside the box to be the sides that stick up so the top will sleeve on. that leaves the bottom panel the same as the outside box.
hopefully that makes sense (since i did it fairly stream of consciousness).
the main point i’m making is it’s not difficult to do the basic two piece box. the harder part is editing to make matching edited edges (and moreso with the extra trim piece in there). but even then, it’s totally doable.