To enable Telegram notifications on your Apple Watch, follow these steps:

Install Telegram on iPhone And Enable Notification Permission on Settings:

• Ensure that you have the Telegram app installed on your iPhone and enable Telegram notification on Settings app.

Open the Apple Watch App:

• Open the Apple Watch app on your iPhone.

Click "Notifications" on the Apple Watch App:

• Inside the Apple Watch app, tap on "Notifications" row on the screen.

Scroll Down and Enable "Telegram" Notification:

• Scroll down to find the "MIRROR IPHONE ALERTS FROM:" section to enable Telegram notification on Apple Watch.

reference link: https://www.rmupdate.com/2023/08/02/how-to-use-telegram-on-apple-watch-series-8/