STM32 STLink send configuration data

I am programming my custom STM32F103C8 microcontroller using the STLinkV2 programmer and platformio. I definitely prefer that over requiring a bootloader, bootpins and programming over UART. But I also want to send configuration data at least at first startup, but potentially later too, to my mcu. I have a separate I2C eeprom chip connected to it where the configuration is saved. I could do that over uart, and make sure the device boots into a “config” mode where it listens for configuratio parameters on the serial port, but that would require 2 pinheaders to be broken out: 1 for programming, 1 for configuration.
So my question is, does anyone have a smart way of sending data from a pc to a mcu through the STLink connection? Like a serial port running over stlink, or another protocol that would work?