For the vast majority of climates, NO.
You are ventilating in terms of square inches when you need to be thinking in terms of square feet. Yes, you need more.
Yes. A lot.
Some metal roofs will sweat in the cold weather with all the moisture that the birds expel during the night and it can drip back on the birds. Having adequate ventilation with proper flow would eliminate some of this concern but I feel metal roofs are just prone to condensate forming on the surface before the moisture has a chance to escape.
I would focus on getting a lot more ventilation in the coop first then consider preventing moisture from contacting the metal surfaces.
This is how my coop is ventilated.
View attachment 3297413
There is a bit over 20 sq feet of ventilation left open year round.
During the warmer months, the windows around the roosts are opened up.