> What problems do you face with whatever 2FA you use?

Ease of migration. I'm currently migrating away from Authy to Aegis. This experience in Aegis is simple because it can import and export the data.

I use gauth [0] on my laptop since there's no Aegis desktop client. This requires adding any new 2FA accounts to both Aegis and gauth at the same time, meaning I need both devices with me. I've not yet tried to export from Aegis and add to gauth separately later, but I'm hoping that will be okay.

> A QR code will be generated on the phone for each login attempt. The website/app where the user is logging in will scan that QR code

Not sure I understand. How will a website be able to scan my phone's screen?