So for common folk like myself, what do I need to do? I used Authy for a few sites. Can a bad actor pretending to be me now get access to those sites?

Bingo!

You’re out if your element, Donny

There is a crude ASCII drawing to represent the circuit

And a quick followup:

If the ground was moved to the T3 junction than the battery’s negative terminal would be common to ground and the voltages values across all loads would go back to being positive in regards to the battery’s negative terminal (T1 = 1000V, T2 = 333V, T3 = 0V) ?