Note that you can click the 'Network Mode' and choose a lower mode than the highest standard your carrier supports.
The list displayed directly under 'Network Mode' is the maximum of what is available and what you select.
On clicking, my phone offers "5G/4G/3G/2G (auto connect)"; "4G/3G/2G (auto connect)"; "3G/2G (auto connect)" and "3G only". So you can lock-out 5G or G5+4G etc right down to 2G only EVEN IF your carrier provides higher.
Perhaps this is to accommodate cheaper plans where 5G might be an added cost option.