Storage archive Strategy

Alright well many years in with my photography and I'm finally fighting for my life with storage capacity as a landscape and wildlife photographer. I currently have 4TB and now need to either consider adding more storage or offloading/archiving. I'm thinking about just buying a 4 tb portable hdd (non-ssd) to maybe archive some older stuff and drag a copy of edited things as well and then remove a bunch of raw stuff and be done with it for the time being.

Couple questions - for those who have archived or have a strategy for eventually archiving - what solutions do you do for this. Can I use Backblaze to back it up for a secondary then delete off my main storage and unplug? I'm just a little nervous that it's prone to eventual loss but I think that would be a long time. The other option would be buy a couple drives and send the secondary off for backup with a family member or something of that sort for safe keeping.

The other alternative is I kill my raws and just use what I kept in finals but I do like to be able to go back and potentially re-edit or re-master some and as proof of ownership is the my other issue with deleting the raws. (Especially in the age of AI now).

Any advice or solutions that have worked well for you? I'm currently running a simple RAID with dual 4 TB drives and Backblaze so I could expand to an even more massive NAS or upgrade to larger drives but I still feel like eventually I'll run into the same issues. It seems wise anyways to once in a while do an archive in some way for further safety anyways since corruption is still a worry or other disaster of sorts is still a worry.