Note that this menu item was not used to install Android apps, which is what people often mean by "sideloading", especially with all the discourse around Google's new developer verification requirements. This menu item was used to manually install an OS update from a .zip file and already required that file to be signed by Samsung on locked devices.
On unlocked devices, you can install your own recovery that still has the option. So the removal doesn't prevent too much in practice. That ship sailed when Samsung stopped allowing bootloader unlocking on most of their phones.
> You don't need to know how a plane/car/elevator works to know that it works when you use it.
I'm sure the 737 MAX seemed to work just fine to Boeing's test pilots. Observing the external behavior of a system is not a substitute for understanding its internal workings and the failure modes they carry.
Is there a reason you wired MOSI and MISO together with a resistor instead of setting the SPI_SIO bit in the ESP32C6's SPI controller? The reference manual[1] says that bit enables "3-line half-duplex communication, where MOSI and MISO signals share the same pin" (page 866). I'm not sure if it's suitable, since the half-duplex mode (see section 28.5.8.4) seems to be designed mainly for talking to SPI flash chips.