Wallcal draws the calendar as a picture. The address always renders
today, so a wallpaper set once is never out of date.
On an iPhone, once:
- Shortcuts → Automation → New → Time of Day. Pick an hour, daily, and
Run Immediately with “Notify When Run” off.
- Add the action Get Contents of URL and paste what Copy gave you.
- Add Set Wallpaper Photo, aim it at the Lock Screen, and turn
“Show Preview” off.
You do not have to wait for that hour to come round: press ▶ on the
automation and it runs straight away.