What exactly about the Amiga FFS made it more fault tolerant?

I’m not sure comparing the file system on a single user workstation where disk is probably quiescent most of the time to the file system used on a busy server is really apples to apples. The Wikipedia article on the Amiga FFS makes it sound like it was an early journaled file system, but not technically superior to anything developed since. It plays back the journal if not shut down cleanly. All modern filesystems do that.

OpenBSD uses FFS btw (not the same FFS as the Amiga).

I ... do not know. I do not know how I came to believe these things. It seems they are false beliefs. The Amiga filesystems were not particularly resilient. I suppose I just finished lying to my parents again. I really should fact-check every damn thing I remember, before talking out my ass about them. I surely live in a fantasy dream world.

Having just read through Wikipedia, though: OpenBSD uses UFS, which layer is referred to as ffs in the userspace. It's potato, potato. The soft-updates should have readily mitigated corruption issues, though they didn't entirely go away. LFS is another component to UFS/ffs, as a formally log-structured filesystem.