My network selection switches from jio true 5g to 4
It keeps switching continuously. And I am in a 5g coverage location
E, 2G, 3G, 4G, LTE, VoLTE, 5G all are Carrier Specific features. Contact your Carrier (Cellular Service Provider), the agency that issued the SIM / eSIM to you. About the LTE options on your iPhone - Apple Support (IN)
See the Pic below and explanations thereof
The pic below is self-explanatory
However iPhone model specific feature is listed here --> Identify your iPhone model - Apple Support . and tap on "See the Technical Specs for Model XXXXXX" under each model and Scroll down to "Cellular and Wireless" section.
Know it here --> All about G, E, 3G, H, H+, 4G, VoLTE, 5GE and 5G symbols ...