Hi. I have been having a similar issue: WP backups created with All-In-One Backup Extension some years ago with PHP 7.4. Unfortunately, the theme, Store Pro by InkHive, is not updatable, at least I haven’t had any response from InkHive (3 times I contacted support), so I am stuck with the last version v2.3.1 and it will not work with PHP later than 7.4. I have tried removing WP, updating PHP incrementally from 7.4 to 8.0 to 8.1, then, installing a fresh copy of WP and then the theme, and it doesn’t work, still get the critical error. It wouldn’t be so bad if I didn’t have six websites using the same theme with the same problem. Any other ideas? Any help would be greatly appreciated.