I know there was concern in the 90s about military exposure to millimeter wave radars, and I’ve never read anything credible about the outcome of whatever studies were done, good or bad. I know that the 24 GHz bands are part of 5G and also related to vehicle networks, so I assume that all major roads will be blanketed with coverage.
My biggest concern with 5G is the FCC declaring every telephone pole “critical infrastructure” and removing or limiting the ability of local governments set rules. In my city, the incompetent response on the city’s part means that Verizon is dropping poles in the optimal (from a cost/radio pov) spot, period. So people have wooden telephone poles in the middle of their lawn. A block from my house, they dropped a pole in the middle of the curb cut for crossing the street, 5 feet from another utility pole. (To avoid renting pole space)