I use iCloud Keychain, and 2FA wherever I can. For this I've mostly used OTP Auth.app: OTP Auth by Roland Moers
<a href="https://appsto.re/th/i4ovN.i" rel="nofollow">https://appsto.re/th/i4ovN.i</a> but I'm also interested in the Hurricane Electric 2FA tool in their network app: HE.NET Network Tools by Hurricane Electric, LLC
<a href="https://appsto.re/th/UQ7jZ.i" rel="nofollow">https://appsto.re/th/UQ7jZ.i</a> as it uses the iCloud Keychain for sync, rather than their own storage format.
I use 1Password with DropBox in order to share between my Windows desktop, iPhone, iPad and Macbook Pro. I also use 2FA with any account that makes it available.
I've got them in a gpg-encrypted org-mode file. Emacs automatically decrypts it when I open it & automatically encrypts when I save. It works well.