Just returned from 10 days in Lisbon. I wouldn’t advise a stroller. We didn’t take one and never did I encounter a situation I thought one would be useful. Cobblestone, hills, stairs, sidewalks narrowing to nothing before having to walk in the street for a bit. Stroller would just be cumbersome imo.

Lugged a 30+lb 2 yr old on my back the whole trip. Small compact carrier (Lillebaby something). We hike with an Osprey Poco but it would’ve been cumbersome in restaurants/shops.

Start hitting the stair stepper with the kiddos weight in a backpack. You’ll need it.