My phone doesn’t wanna update

You can try to update your device from a MacBook or a Windows PC it can go smoother if you do not have enough storage on the device.

Update software on iPhone, iPad, or iPod touch in iTunes on PC - Apple Support

Update software on your iPhone or iPad - Apple Support

1. Do you have at least 6GB of space on your iPhone? If you don't delete some items or try the recommendations in Settings > General > iPhone Storage. Or use your computer to update.
2. Do you have a good WiFi connection?
3. If you are using a VPN turn it off.
4. You need to have at least a 50% battery charge and connected to power.
5. Turn off low power mode.
6. If you have a beta profile remove it.