Do you using a Wi-Fi network or (cellular data , hotspot) ?
is the low power mode on ?
If you update your apps on your iPhone manually do you see any error message or do you facing any problem?
do you use a VPN?
During answers that questions, you can try this steps:
• make sure the date and time is correct:
- Make sure that you have the latest version of iOS or iPadOS.
- Turn on Set Automatically1 in Settings > General > Date & Time. This automatically sets your date and time based on your time zone.
- If a message appears saying that updated time zone information is available, restart your device and any paired Apple Watch.
- Allow your device to use its current location to determine the correct time zone. To do this, go to Settings > Privacy > Location Services > System Services and turn on Setting Time Zone.
- Check that your device shows the correct time zone in Settings > General > Date & Time > Time Zone.
• make sure that you don’t have a school or business account :
Mobile device management (MDM) configuration profiles—typically installed by employers, schools, or other official organizations—allow additional privileges and access to a user’s devices. To look for an unknown MDM configuration profile on your devices, see Delete unknown configuration profiles from your iPhone, iPad, or iPod touch.
• turn off the screen time Temporarily to see if that will solve your problem !