Why is my phone not working on 5G?

Switch between 3G/4G/5G – Samsung Galaxy S10 5G

If you don’t see 5G in the status bar Go to Settings > Cellular > Cellular Data Options. If you see this screen, your device has 5G activated. If you don’t see this screen, contact your carrier to confirm that your plan supports 5G . Turn on Airplane Mode, then turn it off.

Many problems can be solved by simply rebooting the device . Turn your Samsung Galaxy S20 Ultra 5G off, reboot it and check whether the problem has been solved. If you cannot reboot the device the normal way, you can also force it.