I'm using my 5GIf I recall correctly, that's one of the US carriers (T-mobile?) fake rebranding of 4G.
I think they did it specifically to confuse and trick consumers.
5G UC is T-Mobile’s Ultra Capacity network. It includes high-band 5G, but mostly their mid-band spectrum at 2.5GHz.
It's not fake.
If you see 5G without the UC, you're probably on T-Mobile’s low band network.
At my house I only receive 5G, as I live at the base of some bluffs. When I get farther from my home, the network switches to 5G UC & the speed increases significantly.
My mistake, now I need to try and remember what the weird fake 5G one was... I remember the fake 4G was 4GE...