Strength of materials has been a focus of study for many for a long
time. Wood is a very interesting composite material itself, with sawn
lumber having very different properties from the various laminates.
(Ever try to split a piece of plywood?) What is important here is the
orientation of the fibers in the layers and how they're bonded.

When done properly, you can build very stiff, strong structures like
the DeHavilland Mosquito or the "Spruce Goose." Or PT-Boats,
minesweepers, Skimmars.

Duct tape really doesn't even work very well for taping ducts.

Have you considered spaghetti? "Pasta post & beam" maybe? Certainly
better in compression or beam.

Yeah, but you can fake compressive-strength by constraining things
that are strong in tension. That's how inflatables work.
So you make the top half of the "beam" out of long tubes of duct-tape
rammed full of more duct-tape with a mechanical press. Flip the thing
over to get a reverse camber, tape stub-outs made of complete rolls
to the (now upper) surface, and string duct-tape cables along that,
along the stub-outs.

So it's do-able, just stupid.