Chrome MacOS used to store passwords in the MacOS keychain, but stopped. (Not sure if they are stored securely now, but they do not seem to be stored using OS functionality).
Are you positive (not just assuming, cause it would amke sense) FF MacOS still uses the MacOS keychain? Cause that's a plus if so.
(It's also possible to CSV export from Chrome's password manager. I used this to import everything into BitWarden.)