Eras tour to Changi Airport Question

Hi!! Asking for your advice regarding our situation.

We’re attending the March 3 show, then our flight time is 4:30am March 4.

scenario 1: - if we finish the entire show which will end around 11pm, would we be able to reach Changi Airport Terminal 1 before 1am using public transportation? (Side question: around what time does the train and bus end for these occassions?)

scenario 2: - leave around the last two songs so we can ride the public transpo with lesser people around.

Hoping you could help me decide. I really want to end the concert but I don’t want to miss my flight as well.

Thanks for your inputs!