That’s the bootloader. The output is generated before the very first of your firmware is even executed. So by the principle of time travel not being possible, your firmware code can’t affect the output before it.
Of course, Espressif has an option to disable bootloader output, but that is by pulling / strapping GPIO15 low at boot, e.g. by using a strong pull-down resistor (like 1K) or a direct connection to GND, depending on what else you have connected to GPIO15.
I just have one more question. I’m new to embedded system so this might sound silly, but it’s been over a month since I first started working with an ESP32. Until a few days ago, it never displayed any bootloader messages, and ever since I erased the NVRAM with this command : pio run -t erase , it displays the bootloader. Is it simply a coincidence or did the command enable something ?
NVRAM is NVS, which is a separate flash partition. The bootloader is also a flash partition. Could it be that the bootloader was replaced for the first time when you run pio run -t erase? (The bootloader log level is compiled into the bootloader.)