Keep in mind that Fizz does NOT support 5G, and I don't believe that the SIM is 5G capable, so it is possible that because of that the phone does not even give you the option.
More on that on the samsung page at the bottom (under Troubleshooting your 5G connection): https://www.samsung.com/us/support/answer/ANS00083184/
And don't forget...
LTE stands for Long Term Evolution, and is associated with the 4G and 5G wireless communications standard .
So the LTE option that include an "auto" option, it will probably just choose the best available (nicluding 5G if available). I agree it would be better if you had the granularity to select which one, and disable selective ones also.
You can't get true 5G with Fizz
It's normal because Fizz does not offer 5G.
