I bought a pair of Ecco sandals (the hauraches) for my summer Italy trip, and they were the best! They look kind of dowdy online, but are way cuter on than in the photos, and they have a really supportive insole, and really stable almost sneaker like outsole/bottom, so they really hold up for tons of city walking, while keeping your feet cooler than a regular sneaker, and work with dresses and pants.
My husband splurged and got me a pair of Tory Birch flats for Christmas this year (these: https://www.toryburch.com/minnie-travel-ballet-flat–leather/32880.html?dwvar_32880_color=232&cgid=shoes-ballet). After years of wearing el cheapo Target flats, it was AMAZING. Zero break-in period. One of the most comfortable pairs of shoes I’ve ever worn. It has definitely made me realize that, if you can float it, better quality shoes are worth it!