sqlite is a great replacement for fopen - although the C interface is much more verbose.

Oh do you mean as a way to store app state? Yeah 100%. It also helps that there are native reimplementations in many major languages, which means you don’t even need to link a libsqlite3 in contexts where it can sometimes be impractical to use the official C library (looking at you, CGO_ENABLED=0). And let’s not forget about sqlite3 running in wasm :)