Hi Harfeehaziq35,
Please provide your firmware version: Settings > System > About Phone > Software information
Could you tell us which part of the system is lagging?
For 4G not working, please make sure the preferred network: 2G/3G/4G is chosen.
If the problem still appears, please tell us your carrier name, and check if other carriers have this problem as well.
Thank you. 🙂
