All notifications in Telegram are triggered using a specific command that starts with /subscribe, for example:

/subscribe_opportunity_6661a55a66e44c029def2542@UpworkSender_bot

To unsubscribe from such notifications, simply add the prefix "un" at the beginning to form "unsubscribe" and enter the updated command again:

/unsubscribe_opportunity_6661a55a66e44c029def2542@UpworkSender_bot

You will then receive a notification confirming that you have successfully unsubscribed from the notifications.