You need to have oath-toolkit installed with brew
For me personally, iCloud Keychain has the best auto fill experience.
The only problem for me is the luck of OTP support, (It actually auto fill OTP from SMS code)
So, we build our own.
It will ask Safari, which site it's currently on.
Look into keychain to see a token exist, if so use token to generate OTP and fill into your safari automatically.
If not, then it will ask you for a token on this site. Which is the text underline these QRCodes.
Afterwords, it will save it properly in keychain for future usages.