3: RAID-1 pair + manual periodic sync to an external HD, roughly monthly. Databases synced to cloud.

2: external HD is unplugged when not syncing

1: External HD is a rotating pair, swapped in a bank box, roughly quarterly. Bank box costs $45/year.

If the RAID crashes, I lose at most a month. If the house burns down, I lose at most 3 months. Ransomware, unless it’s really stealthy, I lose 3 months. If I had ongoing development projects, a month (or 3) would be a lot to lose, and I’d probably switch to weekly syncs and monthly swaps, but for what I actually do - media files, financial and smart-home data, 3 months would not be impossible to recreate.

All of this works because my system is small enough to fit on one HDD. A 3-2-1 system for tens of TB starts to look a lot like an enterprise system.