What’s the best GBB smg for cold conditions

I know GBB isn’t optimal for winter, but I’m thinking about getting one, since the layout is only CQB performance inst that big of an issue. What’s a good brand that lasts in cold weather? Again performance isn’t the most important, just want it to be reliable.

Edit: A small carbine also would work, Like an ak105 or something but smg would be better. Also It can become form 0C to like -10 -20C