Are you notified if your connecting flight is held?

I'm on a flight that got (1) delayed by an hour, and (2) routed on a 1 hour longer flight path due to weight. Unfortunately this consumed my entire 2 hour layover, and we are set to land when my connection boarding ends.

If United decides to hold the flight, will I get a notification? How early? I'm debating whether to just rebook. Chat (I know....) offered me a flight with a 6 hour layover in SFO that gets me to my destination 12 hours later, but there's 2 direct co-listed Star Alliance flights this afternoon.

Part of me hopes they hold for my flight bc it's co-listed with the national airline for my destination, but I'm not sure if that's wishful thinking.

I'm debating what to do: pray for a held connection, take the horrible flight with a terrible layover and have to sleep in a seat in the airport, or wait til I get to the connecting city and see if I can get someone in person to put me on the Star Alliance flight. Any advice?

Edit: Our captain is apparently a miracle worker and saved us just enough time, combined with the connection boarding being slightly delayed, and I got there with enough time to buy a banana. Huzzah!