Download Calendarly from the App Store.
Open Calendarly and follow the setup to add the Calendarly Shortcut.
Set up the daily automation when prompted. This allows Calendarly to update your Lock Screen automatically every day.
Return to Calendarly and connect your Todoist account.
Choose a layout that supports Todoist.
Customize the layout and choose what you want to show on your Lock Screen.
Run the Calendarly Shortcut to apply your wallpaper.
Your Lock Screen will now show your Todoist tasks and update automatically every day.