I have an iPhone 10 is this able to get 5g?

No. The iPhone X lacks the hardware to connect to 5G as 5G did not exist when the iPhone X was released. Only the iPhone 12 has this hardware.

The iPhone X can connect to 4G / LTE.

Because if you look closely your coworker is on the AT&T network and what is showing on his phone is 5Ge. That is marketing speak for a faster LTE/4G.

Despite your answer that I agree with, I can’t help but wonder, why my coworker has an IPhone XS and has 5G connection, including the 5G symbol in the top right corner. While my 11 pro max does not.

Thank you!