Master Password - what is the best practice?

What is generally considered best practice from a security stand point for your Master Password? (I mean the master password that unlocks your Password Manager, together with 2FA).

\- Memorise it, not written anywhere.

\- Use another password manager for it (e.g. your main password manager is Bitwarden, but you use iPhone/Mac and store the master password in your iCloud keychain)

\- Memorize it, and write a back up somewhere safe.

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