The same issue happens on both iPhone X and iPhone 12 mini which was restored via the backup on iPhone X. Limited or no access to the internet for a few data consumption app over the cellular network (some game, voice or video stream services app etc., not all apps are affected, affected apps can perform 'log in', load thumbnail, but not able to get the video played or get into the main game (Wild rift for instance.). This issue happened before iOS 14 was out, and completely transmitted via backup and restore to new devices. A full network setting reset won't fix it.