Hi Kirk, Thanks for posting here in Microsoft community, since HP Print Smart is a UWP app distributed via Microsoft, try reinstalling it from the Microsoft Store.
If it's missing there, check if your device is managed via Intune Company Portal, which may offer the app. Also, confirm your Windows 10 is still eligible for extended support updates.
What you can try, Check Microsoft Store for HP Print Smart.
If unavailable, try Company Portal (Intune) if your device is managed then ensure your Windows 10 version supports UWP apps.
Also, are you able to find HP Print Smart in the Microsoft Store or Company Portal, or does it show as unavailable or incompatible with your device?
Let me know how it goes.
Chard