I've found the answer, nothing like posting a question to trigger an idea.

I'm using a Waveshare ESP32-S3-Touch-LCD-3.5 development board and it turned out that the pins I'm using are shared with the SD card interface, the MISO and MOSI lines and these have 10k pull ups, exactly as I found. These ...

I've also got questions about the ESP32 S3 ADC inputs. I am trying to read the output of an AD8307 RF log detector. I find that the gain of the device read by the ESP32 analogRead() is half what it should be. The voltages are also higher than expected.

This device provides a voltage output by ...