It wasn’t a health concern. The only concerns for 5G were long-term practicality, energy and service costs and shorter coverage.
5G was supposed to be made for robots, IoT and wireless home internet.
I haven’t tried 5G, but it seems that the expected speeds would be the same as 4G in early days.
5G is actually two completely different radio technologies under one brand name. One of them is just the same thing as 4G but like a little faster, which is probably what it means if you see a “5G” by your phone’s connection strength meter. The other is what people worrying about 5G actually mean, millimeter wave. It’s capable of much faster speeds in an ideal case, but that ideal case involves direct clear line of sight from the device to the tower, with no buildings or trees or hands holding the phone in the way.