When I started learning ML, one of the questions I had was how to initiate surrender. It’s actually easy!
Just tap the gear icon at the upper-left corner, then tap on the red button. See featured image above.
The surrender option is activated after a few minutes [not sure with the exact time] and there’s an interval of a minute after usage of any team member. The game does not currently show who pressed it. 😎
At least 4 should agree to end a game.