Apple ID locked – no access to trusted phone number

I’m trying to recover an old Apple ID where I know the email and correct password, but the account is locked for security reasons. When I sign in, I’m asked to confirm a trusted phone number, but only masked numbers are shown and I don’t recognize or have access to them. There is no option to say I don’t have access to the trusted number, so I’m stuck and can’t proceed with recovery.

This Apple ID was created many years ago when I was a minor, and the only device it was signed into was an iPhone that was later stolen. The trusted phone number belonged to a family member and is now permanently inactive. The Apple ID isn’t signed in anywhere else and there are no trusted devices linked to it.

The account contains important iCloud photos and videos. I’ve tried iforgot.apple.com and different devices and browsers, but I always end up at the same screen.

Has anyone been in a similar situation and successfully recovered their Apple ID? If so, did it require manual review by Apple Account Security, and what’s the best way to reach the right support team?