Account recovery is a proof-of-ownership process. The provider compares what you can demonstrate — a recovery email, a phone number, previous passwords, device history — against what it has on record.
The most common blocker is a recovery method that is out of date: an old phone number, a work email no longer accessible, or an authenticator app lost with a previous handset.
Repeated failed attempts can make things worse by triggering additional security holds, so it is better to gather evidence and submit one careful request than to guess repeatedly.
Everything that makes recovery quick has to be set up beforehand: backup codes saved somewhere safe, two recovery contacts, and a trusted device that stays signed in.