Whenever I looked at using IKEA stuff to hack or incorporate into a larger build, the cost, effort, and quality never seemed worth it to me.
I built my current desk from some butcher block counter tops and shelfs and 4x4's. I don't think it cost me all that much more from what I could have done from IKEA and the quality is astronomically better.
If you're already dealing with saws and drills to hack the IKEA stuff, you really only need to toss is a sander and maybe a router and you can just work with real wood.
A butcher block desk with 4x4s for legs is pretty simple and forgiving. Matching the quality of appearance of a lot of other IKEA furniture would require quite a bit more skill and tools.
Like a Kallax, unless you're a real wizard you couldn't cobble one of those together without a lot of skill.
I have a few of those butcher block tops because I scaled down my shop, but I just can't throw them away. one was purchased 50+ years ago and my family used it as a breakfast table. they make excellent work benches and tables. they're robust and attractive. really all you need is a belt sander and some food safe mineral oil and you can completely resurface them if they get funky. I usually just weld a piece of 1/4" angle to a square plate for legs and weld a nut at the bottom for a threaded foot, but you can really do anything. it absolutely lovely to have a clean butcher block top for food preparation.