Unfortunately, I do not believe Fido offers any smartwatch plans (see here and here) at the moment. You might be able to activate the eSIM, however, it would require its own independent plan. It would not be an extension of your existing Fido number.
Fido made the decision not to offer a smartwatch plan at this time. That's not to say they won't offer one in the future. However, I don't think anyone in this community will know if or when that might happen. Even if someone is privy to that information, they wouldn't be able to disclose those details until it's been publically announced on Fido.ca.
Hope this helps 😀