My iPhone 11max pro won’t update it just says estimating time

Here are some ways to fix it.

1. Make sure your device is charged (50+%), and there is enough free space.
2. Force quit the Settings app (and all other open apps). After that, restart your iPhone and then try updating.
3. If a simple restart does not help, try force restarting.
4. Turn off VPN if you are using one.
5. Restart your Wi-Fi router.
6. Try connecting to a different Wi-Fi network.
7. Check Apple's System Status page. Make sure the relevant services are up and running.

Some other solutions:

1. Reset all settings from the Settings app → General → Reset. After this, try updating.
2. You may also connect your iPhone to a Mac or PC and use Finder or iTunes to update.

Note: When a new update (especially a major one) is released, updating your iPhone or iPad may take some time as Apple servers are busy/overloaded.

Hope it helps!