Other calculator apps that might have different privacy policies, and who might call home to Google and Facebook despite reporting "no data collected", and which might disappear from the app store because it costs $100/year to have the privilege of providing a free app (e.g. as happened with OpenCalc. https://github.com/breeko/OpenCalc/issues/3 )

Believe me, I looked for a while. Nothing quite scratched the itch while also being free, ad-free, and private. I guess I sound quite picky, but SSH + python checks all the boxes.