2021 Tax Refund Claim: Can somebody confirm and show me the IRS publication that states I have until October 2025 if I applied for an extension on my 2021 tax returns?

Many have told me that my deadline is 3 years from the original due date which is 4/15/2025.
However, I read this recently... that the amount of credit or refund you can receive depends on when you file your claim. I was wondering if this confirms that my deadline is 10/15/2025 since I filed for an extension. Please share the irs publication if possible. 

https://www.irs.gov/filing/time-you-can-claim-a-credit-or-refund

 

How much credit or refund you can receive
The amount of credit or refund you can receive depends on when you file your claim.

You file a claim within 3 years from when you file your return
Your credit or refund is limited to the amount you paid during the 3 years before you filed the claim, plus any extensions of time you had to file your return.