Like so many other daily inconveniences, I feel like nobody warned me about this. Here are your three options.
A) Hold them and get really good with one hand. This sounds insane and it is. You will do it anyway. Probably more than once. Probably today. Definitely even when they’re 1y+. You have no idea how strong your upper body is about to be.
B) Leave them somewhere safe. Crib. Bassinet. The middle of their play mat. They’re not going anywhere. If they cry for the 90 seconds you’re gone, they will survive. You will survive. Everyone survives.
C) BabyBjorn bouncer for the win. This was my primary move. Easy peasy, hands-free. Phantom cries not breaking my brain. God forbid you have to poop - now you can see with your own eyes that they’re fine and also do what you need to do. (We went deeper on this one here.)