Backup Unraid Server to External HDDs for offline / offsite backups- Best recommended method without CLI

Hi,

Learned Unraid through spaceinvaderone videos on youtube and it was the perfect solution for me to back up my media files. These are all my own video/photo contents as a content creator. Current server is an archive for all finished work and I'm already at 40TB used out of 50TB available, with expected growth of 10TB yearly at minimum. All Clients are Macbooks or iMacs with 10Gb Networking.

Hardware Specs:

Fractal Define 7 that can accommodate up to 14 drives, Core i3 10105, 8GB DDR4 3200Mhz, Motherboard MSI  Z590-A Pro, Asus 10G Network Adapter, 1 x HBA H310 IT Mode,

1x1TB NME Fast Cache(will upgrade to RAID 1 soon)

7x 10TB HDDs - Mix of Toshiba enterprise of HGST- Two for Parity

I tried doing a backup to a remote site and the upload speed max out at around 20Mbps. On average would take at least a week to upload 1 TB, plus requires constant management, VPN, DNS, etc etc. This is just not worth it for me to have a remote server for replication.

What I need help with is the best way to Sync my folders to a SABRENT 5 Bay 3.5" Docking Station (DS-SC5B). It's an all-in-one box with no Raid features. It's just easier to carry and manage that 5 different external drives.

They will appear as 5 x separate 10TB drives where I wish to sync my main unraid server. However, I've yet to come up on how to sync a file server of 50TB to 5 x 10TB Drives correctly and have some sort of a map to know where to look for my data, on which disk etc.

This seems like a fast copy and enables me to take it off-site. I'll take it about once a month to the office, sync it and go back off-site. Any recommendations appreciated. I have of course gone through the forum and videos for this kind of backup scenario, but there are so many options, and you easily get lost in all the options available and end up nowhere. I prefer GUI over CLI, but if it's simple enough will use CLI also.