Look at the very popular Lack table, it's made from cardboard hexagons with four pieces of wood-like thing in the corners to hold the legs. You can't make that yourself for cheap, and just the material cost in eg. wood, would be more expensive than the full table in ikea.
Otherwise, there are many youtube channels specializing in woodworking where you can learn all the basics to design your own furniture, but it won't be cheap.
In that regard plywood (or glulam) is still wood that can be laminated and stained/oiled, if one insist on wood.
I say this because I’m currently working on a project to build a full kitchen’s worth of cabinet carcasses using good quality 19mm plywood, and I’m aiming for it to be cost neutral with Ikea’s kitchen cabinets, having sourced the plywood from a local DIY store. (Obviously ignoring the cost of my existing tools.)
Which is to say, if you could source plywood in volume (therefore cheaper per square meter) and amortise the cost of the CNC machine and other tools over time, I think it would be feasible to be close to cost competitive with IKEA‘s kitchens.
But CNC isn't the silver bullet. What I ended up with is 25mm glued wood for frames, 55mm for tops and 15mm plywood plus veneer for facades.
If you use 19mm for frames, you won't have enough strength for hinges, which would inevitably be abused.
If you use 19mm for tops, they will sag and vibrate. The best top I have is actually 55mm IKEA glued oak.
For my project, I believe 19mm is plenty for carcasses - just about every mass-produced kitchen uses 18/19mm chipboard frames, and they can last for decades, outside of abnormal abuse. The main reason for using the same size is easy compatibility with standard doors/fronts together with standard fitment hinges/runners, all of which I'll be purchasing. The tops will be either granite or concrete.
Like, using plywood for verticals is overkill, they don't experience any bending, while 19+19 is 48 so you might as well use glued wood board for example.
That seems parameterizable.
ikea is a great inspiration for making your own furniture and then a source for bearable spare parts.
very doesn't even begin to make it justice.