xfs_repair runs instantly, surely this should take some time to run?

0.06 seconds is quite a long time for a computer...

xfs_repair does not read data, it sanity checks file system metadata. A database might have a small number of files, which is a small number of metadata I/Os. Helps that NVMe storage is typically fast. Yes, xfs_repair is complete when it says done.

Getting to the root cause of corruption problems is not easy. Enlist the help of database and file system support willing to stare at block dumps with you. Sometimes the mystery might remain unsolved for a long time, might need to fix storage hardware, restore or rebuild data, and leave it at that.