The original Sensorbox received quite of interest from people wanting to build one for themselves, but it was never designed for that - this one is! Using cheaper components, a more modern microcontroller and a streamlined design for the printable parts, I felt this Sensorbox v2 is something I can actually put out there and recommend you to build as well.
This is a project that hinges on Home Assistant and runs their ESPHome framework, making it easy to visualize the collected data and automate actions based on what you're seeing, e.g. turning on ventilation or air filters. However, it also means that you should have a Home Assistant running on a Pi or in a VM to properly use the Sensorbox - but trying Home Assistant is something I'd recommend to anyone whether or not you're also building a Sensorbox! Nonetheless, there is also a ready-to-flash firmware available that configures the Sensorbox for standalone use without Home Assistant (more info below).
This v2 version also uses a couple of newer sensors that are more easily available. You can mix and match sensors based on your needs, and with the ones that are supported, you should be able to cover most scenarios. It's also now based on a core PCB, which only costs around $5 to get 5 pieces made and shipped. This enabled me to build it around the $2 ESP32-S2 Mini instead of the buggy $6 ESP32-WROVER, adds flexibility for using different sensor loadouts and screens and probably saves you another $2 in jumper cables. So, essentially, the PCB is free ;-)