Since my purpose is to monitor (not measure) battery voltage, I do not need AD conversion accuracy.
Considering current consumption, I divide the voltage by 1/2 with selected 1000k+1000k and do not use a capacitor. I use the value averaged about 100 times.
The accuracy of the ESP32’s AD converter is not very good. Especially when BLE or WiFi is operated, there may be a lot of noise on the input.