Depends on budget and storage options

That’s not much data

Listed in order:

Encrypted nas. For that small amount of data raid 1. A shitty e waste pc would suffice. A ups would be ideal. This is least ideal honestly as it requires power, a maintainer, and isnt truly backup

SSD of some kind, even a usb stick Enterprise hard drive like wd gold or ironwolf pro Redundant copies, 2-3 ideally, store in various cool dry locations

LTO tape - far more resilient than hard drives and cost effective per tb but downside is that you need a very expensive ($3-5000) tape drive to utilize them, also very slow to read/write, older/cheaper tape formats (I believe pre lto8?) don’t have the ability to act as an external disk where you can just drag and drop files and are more of a pain to use

Blu-ray M-DISK. Upside for these are that they are very resilient, can be stored basically anywhere assuming you put them in a sealed container, and will last many many years (probably longer than you’ll be alive). Downside is that storage per disk is very low (100gb), cost per disk is high, and write speed is low. so you will need ~ 50 for 5tb of data, each disk is about $25 (so $1225 though tbf there’s probably bulk pricing) and it would take 37.5 hours to burn them. But this would be the most resilient of all

Cloud storage - backblaze, tresorit, icedrive, etc

Hybrid solution - ideal scenario. Load a hard drive or two and lock them away somewhere. If you have access to a Blu-ray burner maybe burn a handful of m-disks of your most critical data (not all 5tb but the most important 1-200gb or so). If you can access a tape drive do that too. Ideally update the tape and hard drives monthly. Update the Blu-ray as needed. local nas and cloud for daily backups