And one of the first patterns I wanted to use was this. Just a read-only event log that's replicated, that is very easy to understand and operate. Kafka is a beast to manage and run. We picked it at my last company -- and it was a mistake, when a simple DB would have sufficed.
https://github.com/simonw/sqlite-utils https://litestream.io/
I think part of my issue is that a lot of uses of it end up having a big global lock on the database file (see: older versions of Emby/Jellyfin) so you can't use it with multiple threads or processes, but I also haven't really ever find a case to use it over other options. I've never really felt the need to do anything like a JOIN or a UNION when doing local configurations, and for anything more complicated than a local configuration, I likely have access to Postgres or something. I mean, the executable for Postgres is only ten megs or twenty on Linux, so it's not even that much bigger than SQLite for modern computers.
PRAGMA journal_mode = WAL;
One note on the backup/migrate, I think you need a shared lock on the database before you copy the database. If you dont, the database can corrupt. SQLite docs have other recommendations too:
same for redis, kafka, ...