Use something like Backblaze or Hetzner storage boxes for off-site backups. There are a number of tools for making this painless, so pick your favorite. If you have the means, I recommend doing a disaster recovery scenario every so often (i.e. disconnect existing drives, reinstall the OS, and load everything from remote backup).

Generally speaking, follow the 3-2-1 rule:

• 3 copies of everything on
• 2 different types of media with
• 1 copy off site (at least)

For your situation, this could be:

• 3 copies - your computer (NVMe?), TrueNas (HDD?), off-site backup; ideally have a third local device (second computer?)
• 2 media - NVMe and HDD
• 1 copy off site - Backblaze, Hetzner, etc

You could rent a cloud server, but it’ll be a lot more expensive vs just renting storage.