@TheTrench You need to delve deeper into 5G and what 5G is, plus what Android version supports 5G on that device. 5G falls into two categories - 5G Non Stand Alone (NSA) and 5G (SA). 5G NSA piggybacks of the 4G LTE infrastructure end to end in simple terms. 5G SA is full 5G end to end. This can be affected by available networks, service providers, Android versions and vendor BLOBs and device hardware.
You cannot expect newer firmware files to work on an older version of Android without issues or just not working.
I bought a 5G device when 5G was in its infancy and always got 4G LTE indicated and 4G speeds. 5G has a better infrastructure now and it still shows 4G LTE in a lot of cases. My new device is 5G and always shows 5G and is a bit quicker, but not in all cases.