think mayhaps the following is more details having…

To prevent your phone from updating, if only temporarily:

First, turn off updates for your phone.

Second, turn off wireless (when sufficient battery power is available, updates will occur regardless of whether you turned off updates or not).

Third, do not directly connect the phone to any computer or laptop.

Updates can brick your phone if you run out of battery power during the update. The same is also possible if the update becomes corrupted via transmission to your phone.

For both of those reasons, updates via cellular data is only possible if you enable updates and have sufficient battery power.

Note: Recent updates may have removed this safe guard. If so, you may need to turn on emergency alerts again, and the perform the steps above.

Sooner is often better than later.