[2020] Forced to concede against Arena Dev

I was playing sultai Vannifar pod against a dev’s (mythic Orange username) selesnya life gain deck. After what seemed like 40 minutes, I had a board full of growing Oozes and was able to pump out more of them than they could vampire tokens. My only path to win was to wait for my opponent to draw from an empty pile. After a while, my opponent and I both could not do anything on our own turns, we would have to activate abilities in response to each others upkeep/endstep triggers. Eventually it warned me that I would be forced to concede if I didn’t act even though I physically could not do anything, I was no longer receiving prompts. THE TURN they would have drawn from an empty library, it forced me to concede immediately following their upkeep trigger.

Has anyone experienced something similar to this? How could I have won in that position?