what is the maximum amp i can use to power arduino?(using 12V battery)

I want to buy a 12V 6800mA super rechargeable lithium ion battery to power the tank robot & the arduino.
i have attached a photo of the robot , it is not finalized and will add some component if i can (i’m doing it for fun !).
motor voltage is 6-9V
current: 850mA
stalk current 2A

can the arduino voltage regulator handle this ampere ?..i was thinking to use external adjustable voltage regulator ( LM317T ) to control the voltage & reduce current .

if it is not possible then what is the maximum ampere i can use (for arduino only as i will control the current for other components separately) ??

thanks & sorry for long question

Power the Arduino and the motor from the same battery but in parallel to each other. Then the motor will draw what it needs, and the Arduino will draw what it needs.

But you will need to regulate the battery 12V down to the 6-9V for the motor. So you could also use that regulated voltage into the jack of the Arduino, which is good for 7-12.

The Arduino doesn't have to "handle" the current that the battery is capable of supplying: it only takes what it needs; it's the voltage you need to get right.