I cannot see any log through UART0.
I can measure the incoming signal with oscilloscope and it does not show any abnormalities. But it is no response from ESP32.
Modules are integrated in a circuit board with some peripherals (see attached image). Three boards are tested so far.
The µC supply is ...

I try to programm an ESP32-MINI-1 module via UART by using ESP-PROG. Unfortunately I cannot establish communication with the module via UART0. But I get in a programming attempt via UART1 to change the baud rate:

Sketch uses 290325 bytes (22%) of program storage space. Maximum is 1310720 bytes ...