I had replied to your problem with solution. Please check above comments and share your experience.
Did it solve your problem?

The code is now updated as per your valuable suggestion.
Now the connections of the 5+1 switches are changed.
======= Connection details =======
Switches connections:
player1: A0, player2: A1, player3: A2, player4: A3, player5: A4
Judge: A5
LED1: pin-D2, LED2: pin-D3, LED3: pin-D4, LED4: pin-D5, LED5: pin-D6
Buzzer: pin-D7
/* Here at the start of 1st round, judge presses his button.
* So the session starts.
* When any contestant presses his/her button, the buttons of
* other contestants will be disabled.
* In this way, the 1st session is over.
* Now since 1st session is over, the value of x = 2 in the code,
* so any contestant cannot press his/her switch before the start
* of the new session.
* Now when judge presses his button, the value of x = 1
* So new session can start.
* In this way automatic RESET of this circuit is removed.
*/
Please check and reply to this comment.
Thanks for the feedback.

Oh…!
I never thought about this problem of starting the round.
Ok.
Please give me some time, I will try to figure out and write new code for it.

Any solution regarding this ….. BTW thanks for the referral code

That’s great!
We are pleased to help you…!
Please send photographs of the project, so that we will upload them on the same link with your name, so that more people will be inspired from your project to build it.
Please send the photos on our email address: dsvakola@gmail.com

Hey, Thank you very much for the help, Now i have made the project properly working

Well we found out some photographs of the project given on this link: https://vsa.edu.in/ad3-arduino-based-fastest-figure-first-controlling-system-for-quiz-competition/#The_Prototype_of_Project

Sorry. The prototype is sold. We don’t have its photos now.
But I can explain its construction details.
Use two PVC white boards (size: 10″x12″) stuck together back to back, as shown.
The use 5 small square boxes to fit 5 push-to-on buttons with wires and pins for each channel connectivity.
Then install your Arduino nano circuit, or Uno circuit inside one of the stuck white board and connect 9V DC adapter socket on one side of the board.
Connect the adapter externally to start the working.
If you want the project to be readily prepared for you, we can provide such paid service.