Is there a font that would be easy for me to read with practice (and maybe offer some benefits over Latin characters) but would be illegible to normal people reading over my shoulder?
Google turned up a lot of discussions of writing systems for conlangs, but nothing that’s actually usable.
There’s no benefit over Latin characters other than obscured readibilty (and you can write it in any number of artistic styles), but have you come across Elian? There are plenty of fonts too out there.