There is a simple version of this idea that really resonates with me.

For about a decade, I've been using flat files on disk or object storage for most of my side projects. There's even a python library that handles some of the plumbing for you [1].

If you don't have strong record-level concurrency needs then it's a lot nicer, easier, cheaper than a relational or document database. And if you do need that, you can design your data model around what defines a record.

[1] https://tinydb.readthedocs.io/en/latest/