ESP8266 ESP-01s Not Responding, No LED Blinking, Overheating
The ESP8266 is (highly likely) dead. The overheating is the giveaway.
Because you haven't mentioned it, please measure the 3.3V coming out of the Arduino with a multimeter. Unlikely to be the issue but it is easy to check.
You will need to buy a new ESP8266 and connect it up and give it a try with a fresh board. If all is good with the new board then the first thing you will notice is that there is no overheating. (If there is overheating, then you need to check your wiring.)
I notice that quite a lot of people add a 10K pull up resistor between the 3.3V line and the Enable pin. It certainly won't hurt to add a 100 ohm resistor between the Tx pin and D2 of the Arduino as a current limiting resistor, just in case.