LiteFS/Litestream author here. LiteFS will scale to zero with a persistent volume attached. For short-lived instances (aka serverless), we still have a few more features to complete on the road map (e.g. S3 replication, synchronous replication) to make that work well. Pure serverless (e.g. Lambda, Vercel) is also something we plan to support but we want to get LiteFS working well on more traditional deployments (e.g. longer running instances, Kubernetes, etc) first.