Yes, using the backup API you could load on on-disk database into memory and then do the reverse to a temp file and atomically move it to replace the saved copy. There’s even an example of using the backup API for this on the SQLite website

https://www.sqlite.org/backup.html

This wouldn’t be a great solution for large databases, but if you’re using it as a document format up to the couple dozen MB range it’s the perfectly acceptable.

Alternatively you could just go the working copy route - make a copy of the database on open and move it back in place when closed. This would also let you recover unsaved changes if you crash or are terminated before the user hits save, as well as the obvious benefit of not needing to keep the entire database loaded in memory and needing to write the entire thing out on save.