I searched for a bed like this but didn’t find anything I liked that was well-built and affordable. So, I’m building this one out of solid wood for about $450. (Except I had to buy a new miter saw, because my old one was stolen out of my garage about two years ago, so that was another $250.)
Edit:
You’ll need the Measure It addon installed and enabled to see the dimensions. The gray boards are the blank stock pieces I bought. It’s in inches, because I’m a stupid American.
Here’s a screenshot of the blender file:

Edit 2:
I have most of the pieces cut to size. I’ve already made a small mistake, but it wouldn’t be my project if I didn’t. Nothing a little wood filler won’t fix. The side walls of the headboard with the angles I’ll need to cut with my circular saw. Or, maybe I could do it like this. I’m not sure my table saw is big enough. (Also, it was either woodworker or piano player for this guy, I think he made the right choice.)

Edit 3:
I’m stuck waiting for the Vevor pocket hole jig I ordered, and the bed rail hardware. I didn’t get the Kreg, because it’s plastic and more expensive than the more versatile Vevor jig.



Make sure the mattress you’re buying can use a platform.
More than half require slats because they must breathe
I used plywood for under my tempur pedic but drilled 4" holes along it to give it breathing room. Also upholstered it with an old sheet to help with breathing room.
No mold or sagging after a couple years! No huge box spring or cheap, noisy slats.
That seems like a lot of work compared to just using a couple 1x4 but glad it’s working for you.
You cannot just use a tempur pedic bed on slats without their box spring. It’ll sag between the slats.