Authenticator App - Lemmy.one

What authenticator app do you use? How do you backup? Any open source self hosted options?

An nfc enabled Yubikey so I can use it with my phone and computer
Same here. I have two keys (one as backup just in case). I just wish more stuff would support FIDO2 so I don't need to have as many TOTP keys.

I have 2 yubi keys for the more important systems and store the rest in bitwarden.

With your 2 yubi keys, is it possible to set one up as a clone of the other? I've been manually adding to both keys but that's a pain when I don't have the backup with me.

No, you do have to set them up separately/while you have both on hand. Being able to clone them would kind of defeat their point :)