I'm guessing you want more specific guarantees than databases attempt to provide. Like losing only last couple of commits in case HDD or an OS lies about writes

I'm guessing you want more specific guarantees than databases attempt to provide. Like losing only last couple of commits in case HDD or an OS lies about writes, but not corrupting the rest of the database. If this is right, than sure it is possible to do better with something purely log structured with checkpoints. But this is not what SQLite and such databases aim for, they assume you achieve those things with backups.