ok this is the solution works 100% , it seems to me that people who upgraded their phone had this issue and it has to do with i cloud system and how it works after 3 months of searching i found out this solution .
Follow these steps :
1- remove instagram from your old phone (that has the same icloud account )
2- remove instagram from the currnet used phone too
3-go to the settings on (your currnet used phone or the new one) and press on your i cloud id
4-wait for the list to load it ll show all the devices you have linked to your i cloud account
5-press on you old phone and hit remove and press yes and then wait for it to be deleted
6-restart your (new phone)
7-install instagram again and sign in
8-press allow for notification
9-upload anything and like it from another phone and u will start getting the notification back
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