I have a total of 48 TB across 4 HDD, plus the system SSD on my old desktop, now just server. It's unfortunately running windows, because I haven't had the time to reinstall everything from scratch yet even though I've intended to for years.
Anyway, I just run Backblaze for backup on it, except one drive which is important photos/files and that gets an extra backup to a RPi using Syncthing. The other drives are all downloaded media that could be replaced given enough time, but Backblaze backs up my whole PC and hasn't complained about the size yet. I thought for sure they'd cut me off or something, but nope still just paying $99/year for a single PC backup.