If you look closely, you can see the power feed coming out of the top of the street lamp. They make a module that goes in between the street light and the photocell module that will pull some power off the light circuit and feed the radio.
Since it's on a street light, it's probably something for the city.
It's not cellular, not 5G.
Like I said above, probably meter reader, 900MHz stuff. Two antennas like that are often diversity setup, so probably trying to talk to something low power, like water meter, power meter, gas meter, etc.
You could also try searching the wifi nodes in that area and see if there is anything new, especially something city related.