And how did you upgrade from Gitlab 14.0.0 to 17.4.2? Direct? Or did you follow the upgrade path?
If you did it direct and didn’t follow the upgrade path, then you will need to restore your server to version 14.0.0 and follow the upgrade process correctly ensuring that the upgrade path is followed, and between each upgrade you ensure that background migrations have finished before starting the next upgrade. This is all explained in the Gitlab documentation, and a lot of links for that can be found here: GitLab Upgrade Path Resources