The world is moving forward with 5g network services, which provide seamless internet speed all across the globe. If your phone is 5g compatible and still 5g not working on your mobile. The thing you can do to fix this issue is enabling airplane mode and after 1-2 seconds turn it off. This process will disconnect your network from the tower and reestablish the connection again.

Source: https://getassist.net/5g-network-not-showing-up/