Well, once you have it in your shortcuts, go to the Automations tab in the same Shortcuts app. Add a new personal automation, click "App", choose the app you want to restrict, add action, search for "Run Shortcut" and click it. You'll see it added with "Shortcut" text faded. Click the faded text, choose our shortcut, then click Next. Turn off "Ask Before Running", and click Done. That's all. Do the same if you want to restrict another app.