Almost certainly a 5G monopole mast. They don't have external panels. We have several around here including the one that serves me. All those cabs at ground level look identical to ours.
I see little point in them installing only 4G in them.
Connections: OnePlus 8 Pro on Three 4+ (LTE)/5G and at home Three Mobile, with (Three)ZTE MF286D router giving about 113/20Mbps.