Crate or childs travel cot for a new puppy at night time?

I’m getting a new puppy in about a week. I already have an older dog and i’m going to put up a puppy pen for keeping the puppy separated from my adult dog while not being supervised or for when my adult dog has had enough with play time.

I dont plan to use crates once shes potty trained and safely integrated with my adult dog.

For the bedroom at night where theres less room, i want to keep her separated from my bigger dog but still close together so they’ll hopefully grow use to each other without her being able to irritate him whilst we’re asleep and risking her getting hurt if she pushes her luck too much with him.

I had the idea of using a babies travel cot that i can get very cheap second hand on FB market place. Is this a good idea or would i be better off getting a traditional crate to keep her safe while we’re sleeping?