Using esp_light_sleep_start() can break WiFi, should be configurable to use delay()/xTaskNotifyWait() instead.

[ranma]

With the default of esp_light_sleep_start() I see WiFi connection problems.

Using delay() can still noticeably reduce the SoC temperature. In my limited testing, the temperature reported by CpuTemperature.read() reduced from ~58 °C to ~52 °C after enabling -D_TASK_SLEEP_ON_IDLE_RUN=1 and hacking it to use delay() instead of esp_light_sleep_start().