Hey Afallen,
If the issue seems to occur when using an app that requires internet access, it may be related to the network. Does this happen when using cellular data, different Wi-Fi networks, or both?
If it only occurs when using the cellular network, we suggest contacting your wireless carrier for help. They will be able to further look into your network status.
If it seems to occur when using a home Wi-Fi network, test a different Wi-Fi network possibly in another location to help determine where the issue lies. If it's just with the home Wi-Fi network, contact your Internet Service Provider for further assistance. They are the experts in regards to their service.
If it happens with app that needs internet access as well as apps that do not, follow the troubleshooting steps below. It addresses slow performance. For additional information about each step, click on this article: If your iPhone or iPad is running slow.
• Check your network conditions
• Close an app that's not responding
• Make sure you have enough storage
• Turn off Low Power Mode
• Keep your device from getting too hot or cold
• Look at your battery health
If the above steps do not improve the performance, review the section labeled "Get more help". There's a link there to contact Apple Support for additional help. They should be able to investigate this further with you.
Take care.