I have the situation where I have customers who have backups on an older Commvault infrastructure and they want to move their Backup service with another provider without losing the long retention backups.

I don't see any other possibility than importing tapes or restoring and copying old backups. Both options do not seem viable to me.

I don't think so, but I wanted to ask the community if anyone knows of a way to transfer those backups between Commvault infrastructures.