I am going to Portugal next week and am facing similar decisions. Neither of those bags are super obvious designer bags, so I don't think you have to worry about attracting negative attention as you might with other bags. A friend has a medium black flamenco and loves it. I think it would be a good travel bag because it is casual and can be worn crossbody, but it can also work for nighttime, and more packable than a puzzle if you're not carrying it in transit. I might buy one in while in Lisbon. My go-to bag while in transit is a black nylon zip top
Prada crossbody that is very functional and durable, but I'm also taking a black
Loewe Missy bag from 2018 that's a bit dressier for evenings. It also has a zip top, sits close to the body and holds quite a bit. For me choosing handbags and shoes is almost as hard as choosing clothes for a trip. Have a wonderful time and buy yourself a nice Christmas gift while there!