I think this is more of a return to the status quo.

10+ years ago there were 2 big names in open source embedded databases, Berkley DB, and SQLite.

Then the NoSQL fad hit, and a bunch of new key value stores emerged. Now developers are remembering what made relational databases great.

Even when you don't need relational features, SQLite is battle tested, and a great choice for storing key, value pairs.

well, not only lately, SQLite was always very popular

My personal opinion, is that the relational model is the best option to model data, any attempt to avoid it, replace it, mimic it adds more complexity than it solve

Linked Tables (relations) is the ultimate data modeling tool

SQLite has been the most widely used SQL database worldwide for at least a decade if not more. https://sqlite.org/mostdeployed.html