Local installation: Available two-factor authentication (parallel use)

I am a user on a local installation, not an administrator.
The admin referred me to this forum.

Unlike this forum, GitLab do not see the possibility of depositing multiple tokens. Is that correct that concurrent is not possible?
Hardware can fail, be lost or stolen. Do only the backup codes serve as backup?

The resource
Two-factor authentication | GitLab only gives information about the different methods, as far as I can see, but nothing about their parallel use.

In the long term, I would like to connect several TOTP apps as well as a Yubikey and a Nitrokey. Is this possible?

Thanks a lot

Hi,

Actually no, it seems only one device is possible. So either codes via Authy, or U2F device like Yubikey. But as long as you upload an SSH key to your account before losing your 2FA device/codes, then you can regenerate new codes to gain access to your account.

The reason I mention Authy instead of Google Authenticator is that Authy can backup your accounts, therefore if you lose the phone, it’s enough to restore the app to a new phone, and then provide the password to restore your account. Or like I do, I have two phones, and use Authy on both, using the same account. Works great.