Sounds like the ESP32 is dragging the whole toaster’s power rail down. First thing: check that you’re feeding the ESP32 its own 3.3 V regulator from a clean source, not the toaster’s 120 V‑to‑12 V adapter. If you’re using a buck from 12 V to 3.3 V, make sure it’s rated for the current the camera, Wi‑Fi and any LED backlight draw. Add a 100 µF bulk cap at the regulator output and a 0.1 µF ceramic right at the ESP32’s 3.3 V pin. Ground the camera and the ESP32 together, but keep the toaster’s mains wiring isolated. If the spike still shows up, place a 10 nF filter cap on the 5 V line feeding the camera and a 22 µH in series to suppress transients. Finally, monitor the voltage with a DMM while the ESP32 wakes up and checks the current draw with a shunt or a current probe; that will pinpoint whether the issue is the regulator, the camera, or the toaster’s own voltage drop. Once you isolate the culprit, swap in a higher‑current regulator or a dedicated power path for the camera, and the rogue squirrel should quiet down.