Oh, that actually surprises me. Are you sure nothing else changed?
Maybe the actual fix was that you made some memory available? How much free space was available before you made the changes? (You might want to revert the changes, now that you still know what you did, and take note of what the Arduino IDE tells you during upload.) I’m not sure if a sketch that uses 100% of the available program space is actually bad for Arduino.
Aside: note that DISABLE_MCMD_PingSlotChannelReq and #define USE_IDEETRON_AES were just one of the many example from the README; there are many more options, such as, for example, #define DISABLE_PING and #define DISABLE_BEACONS that can free some more memory if you need more to program space to handle some sensors.
I very much disagree for images that basically are text, such as the output of the Arduino serial monitor and compiler. The images are super small on a mobile phone. And people cannot search for the text in the images, or copy text (including the URL from your error message!) from the images. Also, the forum has options to format text.
If you want to just check some input using some timer, then many examples of, e.g., temperature sensors will be a good start. If you want to sleep until the switch changes state, then you need to search for “interrupts”. Maybe Arduino pin interrupts helps, but I’ve not read it. Beware that there’s no real guarantee that the radio transmission is received.