I no longer consider any of this to be valid, and consider this entire adventure so far to have been intellectually dishonest and filled with questionable assumptions about everything, so, please, if you're reading this and got linked here, stop reading this and tell whoever linked you here to shut the f**k up already.
UPDATE: This (and, therefore, the promised bug reports) has been put on hold until I get around to getting actual evidence with the herein-mentioned RPi Pico + photoresistor setup, which is itself "delayed until further notice" because I simply have better and more important stuff to do[^1] right now.
UPDATE 2: Some madlad actually did it, only for GNOME though but that's still amazing
*UPDATE 3: Apparently, it's like this on purpose, at least