Safari Passwords and 3rd party apps can and do use the Apple Keychain on macOS/iOS to store sensitive data. Though 3rd parties can't integrate with Safari's password manager.
If you use Chrome Sync with passwords on macOS, Chrome actually stores the decryption key in the macOS keychain. Just open Keychain.app (/Applications/Utilities/Keychain Access.app) and search for "Chrome Safe Storage" to find it. That's the decryption key for the actual encrypted password/sync data stored elsewhere. (So not possible to access Chrome passwords from the Keychain directly)
Safari Passwords (Apple's password manager) also stores passwords in the Keychain as individual entries and you can access them via Keychain.app. Unfortunately, since they’re part of the iCloud Keychain not the local login Keychain, they appear to be inaccessible with the `security` CLI tool which fails in an obtuse way.
If you use Chrome Sync with passwords on macOS, Chrome actually stores the decryption key in the macOS keychain. Just open Keychain.app (/Applications/Utilities/Keychain Access.app) and search for "Chrome Safe Storage" to find it. That's the decryption key for the actual encrypted password/sync data stored elsewhere. (So not possible to access Chrome passwords from the Keychain directly)
Safari Passwords (Apple's password manager) also stores passwords in the Keychain as individual entries and you can access them via Keychain.app. Unfortunately, since they’re part of the iCloud Keychain not the local login Keychain, they appear to be inaccessible with the `security` CLI tool which fails in an obtuse way.