Olimex ESP32-POE Reboot Loop

Did you have Ethernet (non-POE!) connected to the board during start up, and did you monitor the serial output in VSC/PlatformIO to see the startup log?

With the suggested build_flags above there should not really be any need for a portal to enter any information when starting the board.

And could you post your custom environment, in case some of the (possibly also missing) BME280 definitions are causing a problem.