Pure OpenOCD debug with ESP-PROG


I am using PlatformIO version 6.1.14 and OpenOCD v0.12.0-esp32-20230419. I would like to estabillish a pure debugging session (for instance using Telnet) using only OpenOCD without the PlatformIO debugger. How is that possible, how to configure the custom debug server?

My board is ESP32-WROOM-32D (Firebeetle).
Thanks in advance!