I really like packing a maxi costume or two to get a summer trip—they’re attractive and comfortable whilst also staying light and easy to pack. I’d also carry together a light jacket or cardigan, as summer evenings in Austria (especially if you’re through the water) could be a bit chilly. https://tedomarket.com/product/shoes-2/mens-shoes/boots-mens-shoes/chelsea-boots/patent-leather-men-chelsea-boots-pointed-classic-retro-mens-italian-dress-boots-formal-short-boots-big-size-48-shoes/