I found out that unifi plug in doorbell chimes use an esp32 this way because I saw one on my devices table, before it had booted fully and handshook as it's real Identity

Do you mean the non-PoE version? I have the PoE version sitting in a box somewhere and I'm a ESP32 enthusiast so I'm wondering if that's what I'll be doing today. Surely they're using it just as a WiFi coprocessor? Or...?

The non PoE one, the one that just plugs into a normal power outlet

My PoE one has only ever identified as what Ubiquiti thinks it is, so no idea