As many Apple Watch users have discovered, there is no way to connect a bricked watch to a Mac to manually restore the software like you can with an iPhone or an iPad. Your only hope was to take it to the nearest Apple Store (or send it in to Apple to be reset) if it conked out during an update or because of a software bug. But now, as long as your Apple Watch is updated to watchOS 8.5 and your iPhone is running iOS 15.4 or higher, you can use your iPhone to reset your watch wirelessly.
How to manually reset your Apple Watch
Put the Apple Watch on its charger and bring your iPhone near it. If the watch is showing a red exclamation mark, double-click the Digital Crown button so it can start looking for nearby iPhones.
Make sure the iPhone is unlocked, the Bluetooth is turned on, and wifi is connected to the local network. Double-click the side button on your Apple Watch — an Apple Watch pairing pop-up will appear on the iPhone, but with the option to recover the watch instead. Press “Continue,” and follow the process to restore it to its factory settings.
If you don’t see the pop-up on your iPhone, try using a 2.4GHz network instead of a 5GHz network. Also, makes sure you’re not on a limited network, or on an 802.1X network, and try again.