Thanks! Glad you found it useful. SQLite actually works really well for tons of applications where people often assume you need Postgres, and the simplicity of setting it up and backing it up is extremely compelling.

You can really help things a lot with the PRAGMAs, and if that doesn't work, you can use something like an async DB write queue pattern to deal with the simultaneous write limitations (and also by doing more stuff with transactions and bulk insertions).