Problem
Sometimes it's quite stressful to type in the 2FA time code during login. Subsequently realising that the time code wasn't entered due to an unfocused input field doesn't help.
I know that 2FA probably accepts codes +/- 1-2 time steps in order to handle clients with somewhat inaccurate clocks. This isn't about that, but about UX for twitchy users. ;-)
Suggestion
Enable focus on the input field when the page loads.