apple watch update to 11.1 taking forever. estimated 7 days.

That’s way too long! Try these steps:

1. Make sure your iPhone and Watch are on the same Wi-Fi network.

2. Restart both devices.

3. Keep the Watch on its charger during the update.

4. Pause and restart the download in the Watch app.

5. If still slow, unpair and re-pair the Watch, then retry the update.

Is your iPhone and Apple Watch connected to the charger and the same Wi-Fi network during the update process?

Have a look at this related article, especially the "Need more help with updating" section at the end of he page.

Update your Apple Watch - Apple Support