If you are storing manly on one device and are looking for a relatively "simple" solution for encryption at rest I would suggest to just encrypt the folder/directory/image the data are living in.
Of course, this way you have to decrypt the data while you are using it. However, it separates the responsibility from the note taking app.
This may or may not be a good solution for your use case, but it should be fast and easy to implement.
I used to do this with some mildly sensitive data using a mac encrypted disk image with plain markdowns files inside. I accessed the files with vscode, but I don't see why it wouldn't work with Obsidian. It may just be a bit of a hassle to open the vault each time.
Good to know, but this is a security risk of the note taking app, not of the encryption method itself.