Help with pulled up pin and resistor values

[danski]

I'm using an Olimex ESP32-POE. I am really struggling trying to understand why GPIO pin 13 is always pulled high and what I can do about it.

I am using Esphome, and nothing I do seems to switch off the (presumably) pull up resistor that's causing this.

I have tried pulling down the pin to ground using resistors but I can't hit the sweet spot. The board seems to determine high vs low at about 1.8v. So I need a resistor value of about 2K I would think!

But it just seems baffling to me that it should work like this.

Any insights? Related thread

Many thanks!!