5G and 5 GHz Wi-Fi/5.x GHz RF are NOT the same thing.
5G in cellular terms only means "5th Generation". It has nothing to do with the frequency. Cellular frequencies vary by country and even down to individual towns and cities.
You would need to find what band(s) your nearest tower (for your carrier) transmits and receives on and then build your infrastructure accordingly. Not sure how easy that is in the US, but in Australia, all towers, carriers and frequencies are publicly available via
https://www.rfnsa.com.auTo give you an example, 5G cellular in Australia are mostly on the 3500 MHz band, with some carriers also operating 5G services on on 700-850 MHz, 1800 MHz, 2100-2300 MHz and 26 GHz. 2G is no longer a thing here and the last of the 3G services will be switched off by September this year. At that stage, frequencies previously used will be re-purposed for 4G/LTE and 5G services.