Inspired by the many really good boxes here, I have developed this design. What bothered me so far was that the display is always placed vertically in the box, which always makes the readability a bit difficult depending on the location. So I angled the front slightly backwards so that the display looks more in the line of sight.
I printed it with PLA-CF from Bambu. Support is only needed for the version with display cutout. Here I used Tree-Support.
The thermometer/hygrometer I used was the "Thlevel Mini LCD Digital Thermometer Hygrometer" from Amazon. For comparison, I had all three lying next to each other for over an hour (see last photo), and I think these very minimal deviations are acceptable.
NOTE
As it has often been noted here that the printed housing has broken when installing the hygrometer, I would like to point out that the clips on the hygrometer must be cut off before insertion. If these clips are removed, the printout will not break.
Play around with a realtime rendering of the model.
NEW MODEL
If you have printed this model, then you might also be interested in this one: The "Bambu Lab Lid Riser" with many features. It's brand new. 😎