I convinced my boss to let me sell these as open source since we found many cool IOT uses for them around the office as well, that's why you are getting the RS232 on there but most people probably will not need that feature, but hey... it is there if you need it :)
Esp8266 doesnt have flash encryption and secure boot. Esp32-s2 does though.
I have the opposite experience. Sure, if you just need to adapt their examples a bit, it's quite smooth. But the documentation is horrendous! If you need to do anything non-trivial that isn't covered by examples, I found it very very hard to work with. The documentation barely exists and is written in poor English. Compare this to the documentation for ARM SDKs, for example! Night and day.
esp-idf worked on the first try.
rs232 can run quite long distances.