Confusion/Questions about encryption key

[GamerBene19]

I want to decrypt my .crypt14 file(s) with the goal being to ready my messages in plaintext without a need for WhatsApp.

As far as I understand it, the .crypt14 files are encrypted with the key stored at /data/data/com.whatsapp/files/key which is only accessible on rooted phones. As I am not able to root my phone, I am looking for another way to decrypt my database(s).

If I understand correctly, an alternative to the .../key file is to use the 64-letter key that can be set/viewed when enabling E2E encrypted backups.

I am a little confused about that process as the README states both

1. Enable end-to-end backups and do NOT use a password, use the 64-letters key option.
2. Use wacreatekey to create a encrypted_backup.key file

and

If you enabled E2E backups, and you did not use a password [...], you can just transcribe and use it in lieu of the key file parameter.

which reads like I can and should use the 64-letter key directly and do not need to use wacreatekey.

Also I'm wondering whether the .crypt14 files on my phone do get (re)encrypted with the 64-letter key if I enable E2E encrypted backups, or if that key only affects the backup files stored in Google Drive.

If the latter is the case (the key only affecting the Google Drive backup) then the 64-letter key would be useless for the .crypt14 files stored locally on my phone and I'd have to find a way to download the files from Google Drive, correct?

Would be nice if someone could clarify the process and answer my questions. Thanks in advance for any help!