ESP32 and IDF: UART pin selection, GPIO, pin numbers and tutorials

Hi I am starting to use ESP 32 idf. But I have some problems and questions.
1. they state that there are 3 uart and I only see 1 https://docs.espressif.com/projects/esp-idf/e...est/esp32/_images/esp32-devkitC-v4-pinout.png.
2. with these esp and programming in idf is it so that you can choose any pin ? That for example the uart does not have to be permanently in one place ?
If so, what happens to the pin from which we redirected the uart ? Can it be used or is it wasted ?
3 If it is as I write in point 2, which pin numbers should I look at ? the gpio in green or the ones on the board ?
4 There are some cool tutorials for this. Because I can't find any that make sense maybe I'm looking wrong ?
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I would still like to ask if you have also perhaps used the arduino ide for the esp32. How does it compare to the idf?
Is it possible to do something more difficult there than flashing a diode in arduino ide ? If there was no idf would you then choose it as an alternative ?

Is there any converter from arduino to esp idf code ? Since these are overlays ?