The instinct is to solve sunlight with nits alone. Buy the brightest panel, point it at the street, done. It works for about a season.
Brightness is the first decision and the easiest: 2500 nit behind glass on a shaded frontage, 4000 to 5000 nit facing the sun. Panel structure is the second — an M+ blackening-free panel keeps its blacks behind heated glass where a conventional panel greys out. The polarizer is the third: a circular polarizer keeps the image visible to people in polarized sunglasses, which outdoors is a very large fraction of your audience.
Thermal design is the fourth and the one that gets skipped. A bright panel behind glass generates heat and also receives it. Without a temperature sensor driving a fan, the panel throttles its own brightness exactly when you need it most. Mounting is the fifth: angle and depth relative to the glass change reflection more than a thousand nits do.