That's honest and worth hearing. The dogma around "SQLite isn't production-grade" does real damage. That said, I'd push back slightly on the audit log setup.
WAL mode helps, but you're still limited to one writer at a time. If your audit logs become a bottleneck later (and they often do under load spikes), you've got nowhere to scale without rearchitecting. Moving to a separate file buys you some breathing room but doesn't solve the fundamental constraint.
For your use case sounds fine. But I'd be explicit about the failure modes you're accepting: no distributed writes, single machine failure, specific backup complexity. Document it so the next engineer doesn't assume it's infinitely scalable.
What does your monitoring actually show for write contention over time.