Real world experience - PT session/studio archive setups?

[Actionmusic]

Running our productions for 10+ years now. First few years could back up to small hard drives with long term backup on AIT. we've never had to look at the AIT's from that period! We seem to have come to a place where we're just recopying old hard drive backups onto newer (larger) disks. Whereas 1tb a few years ago took a couple of years to fill, we're now generating that amount of data in a few months or so.

1tb is the sort of "unit" size I want to backup. It's copyable onto a portable drive. When that engineer or session drive is full I want to archive (we're doing daily backups during sessions).

So currently we do this by duplicate drives , large 4tb , consumer units, and dump say 4 drives worth on. No raid. Then a dupe of the same physically kept somewhere else.

So , questions:
Anyone got a modern solution to this ever growing data ? new medium's or just duping drives and leaving somewhere else like we do? something flexible but robust without the old painful restore from tape?

One thing that has happened over the last few years which is immediate gratification but not necessarily good practice long term is that sessions have been recalled/tweaked direct from hard drive backups , any tweaks then saved as a new PT file. However, recent PT versions can change older SD2 etc sessions so data is shifting, and that backup is no longer the same as the backup on another drive that was originally its clone). That's a slight worry

To cut to the chase.... for a working busy producer based PT studio, what are you using for getting a hold of this issue ?