Itunes and backups

Hey gang,

I recently bought an iPhone 12. Prior to go buy the phone at the Apple store I downloaded Itunes on my work laptop and made a backup of my iPhone 7+.

I exchanged my 7+ at the Apple store so I don't have access to it anymore.

Went I came back home, surprise, the backup was encrypted. I tried every password known that I could have used there but no success.

I have a previous backup on my personal laptop, this one is not encrypted, but seems empty.

I read a lot of post about those loss backup passwords. It is depressing to see that after so many years Apple has not do anything about it. I personally just want to get my photos back.

I have multiple questions:

• Why is the encrypted box checked even though it was a fresh new iTunes install?
• Is the encryption password linked to the backup itself, or the device, or iTunes? The phone previously belonged to my brother-in-law and I was wondering if even after a reset of the phone it could be his password for the backup. I had iPhones before, and was wondering if I could have set up a password before on previous devices that was carried on this one (though one backup was not encrypted...)
• If the box is checked, that does mean that a human checked it right? Or can it be a legacy of some security coming from the laptop? Has I am using my work laptop.

It is very frustrating, knowing that I could have exported those photos and videos outside of the backup. But still, seeing that many people with the same issues should raise flag at Apple.