Consider there is single button (dynamic) one, if user didn't choose for more than 5 sec it should proceed to next card, how to achieve this?

I don't think there is a good way of doing it right now

If i included a single choice card. i have to wait for user enter input?

That is correct, you would have to wait for an input from the user. I am not sure if there is another way to display buttons, but not waiting for an input. Maybe another @User knows

just a thought but what about creating a timeout() function that awaits the event.preview() (on.button.clickevent ?) and if it doesn't receive input it triggers the next node. @fresh-fireman-491

Might be, but how would you allow for a button?