The sonoff line is typically pretty hackable and now has etl certification on some of their products. If recommend something like this if you want to switch mai

The sonoff line is typically pretty hackable and now has etl certification on some of their products. If recommend something like this if you want to switch mains voltage. I use tasmota, which is similar to esphome. The tasmota wiki has disassembly and flashing info. I've always used wires to flash mine but I think there's a software only flash method. The s31 can be flashed with some spring hook probes and the appropriate rs232 cable (3.3v on the data lines iirc). Some of the in wall line need a few pins soldered on (typically 4). Tasmota has a setup package of you don't mind manually setting up each device. You can also configure them with code if you learn a little c and platformio. At this point, I batch my devices and flash them with wires for initial configuration (Wi-Fi, mqtt, etc), then run updates wirelessly using an http server on my network and mqtt to coordinate. Side note, the esp8266 is older and less powerful than the esp32. In practice, the esp8266 can't handle https but the esp32 can. This has never been an issue for me and most of my devices are 8266.