If you were not already aware, iPhone 12 was the first model ever to introduce 5G enabling in iPhones. When it first launched in April of 2021, it was the first iPhone series, all four of the iPhone 12 variations, to have the option to use 5G.
Slow or bad 5G service and speed can be truly frustrating if you have experienced it.
However, if you still find that your 5G is working quite less than well and that you might have a much better connection with a lower-speed cellular service, you can also do so manually from settings.