Buy Yubikey, put SSH key on Yubikey, job done.
You can use Nitrokey too, but IIRC be careful which one you buy as some are software-only implementations.
> You can use Nitrokey too, but IIRC be careful which one you buy as some are software-only implementations.
First I've heard of this. Do you have some links where I can read more about this?
You can check this guide: https://github.com/drduh/YubiKey-Guide