DIY Perks also attempted to make artificial sunlight at home, also focusing on things like Rayleigh scattering! This was a great watch:
https://www.youtube.com/watch?v=6bqBsHSwPgw
EDIT: After reading the article, I see the OP calls out DIY Perks specifically - the OPs design is much more compact :)
> It's compact. The total size is 19cm x 19cm x 9cm. This is quite compact for a 5cm focal length and an effective lighting area of 18cm x 18cm. Reflective designs like the DIYPerks video or commercial products like CoeLux do not achieve this form factor.
If you want a jankier but cheaper version, here's a (much less nice) version for about $50: https://worstplans.com/2021/05/10/led-artificial-skylight-fo...
It uses a trash can plus a super-bright LED bulb plus a plastic book magnifier.
The main trick is that you can get a big magazine-sized flat plastic fresnel lens for like 10 bucks.
The original poster's solution is definitely better, but it's also possible to do this on the cheap with no 3D printing (or in fact, any skills whatsoever).