I just recently spent time trying to decide on a pouch. After finding "faults" with all of them, the SA showed me this:
https://us.louisvuitton.com/eng-us/products/pallas-beauty-case-monogram-014696
I know it's part of the women's collection...but its a pouch. It's pretty gender neutral.
It's the perfect size. It has a pocket with a magnetic close on the outside. It has a zippered pocket inside and it's really pliable canvas.
It works great i a carry on or packed in luggage. It's not rigid at all.
It comes with red or black accents. Ive had it a while now and it's one of the things I reach for the most.