Keep in mind that many (all?) of these sensors are 5 V and many boards are 3.3 V these days but might have inputs which are 5V safe. The Raspberry Pi is 3.3V, and I think that includes the
Raspberry Pi Pico is too. Also note which models of sensor are analog and which are digital.
The ESP32 mentioned in the Reichelt link there has more than a few varieties, some with bluetooth and wifi and others without. They are low power and you can get a Lithium Iron Phosphate (LiFePO4) battery for it, but you probably won't be able to use a regular mobile phone power bank for it. The ESP32 draws so little power that the power bank will shut itself off. As for the LiFePO4 batteries, there are charger boards which can be attached between the battery and the ESP32, since the reality is far more complex than just connecting wires to a battery.
You may have to 3D print a case. There are mail order options for that and some libraries and Maker Spaces might be found locally.
If you're looking for an almost ready kit, the
MagTag from Adafruit has a built-in e-paper display, built-in buttons, a built-in buzzer, an accelerometer, four NeoPixels, and a built-in Lithium Polymer (LiPo) battery adapter / charger. It can be programmed either the usual way or with CircuitPython. Keep in mind that LiPo are the same kind as in mobile phones and therefore will explode and catch fire from many situations.
If you do find something, please post about it!
Edit: About the question of CO2 sensors, here is one:
https://www.olimex.com/Products/Components/Sensors/Gas/
DIY CO2 monitor?
