Make a timer variable and have it start when voting commences. Make a timer window for it if you want.
Make a new trigger that runs when the timer expires. Put the "all players ready" condition function that I made as a condition and set it to false.
For the actions, make a "Pick Each Player In 'Voting Players'" action with a "If - then - else" action under it.
In the condition for the "If - then - else" action put my "Player Ready" variable, index [picked player], and set to = "false".
Copy from the vote trigger the vote action that you want the player to vote for when the timer's done and paste them under the "Then" actions.
After the pick each player action (make sure this is not in the loop), put a "Run Trigger 'Ready Check'" action.
This way, when the timer runs, it will check if there's any players that haven't voted yet. If there is any, then it will automatically vote for them.