I am used to XE just because I’ve used it since, like, forever. I just uninstalled and see if this app Currencies fits the bill.

I don’t have an account there, I only use the app when I need to know what are the rates at that moment.

Not FOSS, but XE is what I use for currency exchange

Pair it with the arrsuite and chef kisses

Nice homework you got there. Imo you need to read the manpages for cron or systemd timers, to schedule your tasks. Any cloud based calendar app can help you for the notification. And I think any genai tool can get you a suitable chunk of code depending on your specifics about the scripting.

TPM storage, perhaps?