Apple Watch will not connect to iPhone 15

I was having this exact issue all day! While transferring my data from an old iPhone to the new iPhone 15 Pro, my watch "froze" in the process of transferring, and thereafter wouldn't connect to my new phone. I repeatedly tried to connect as both a new and existing watch but was never successful. By this point, I'd already wiped and turned off my old phone, so my top priority was to not have to turn it back on and confirm my watch data was off of it. Without going back into my old phone, the solution that worked for me was:

• powering off and on the iPhone 15
• powering off and on the watch
• once on, going into the watch settings and selecting the reset option. This initiated another automatic power-off, so then I powered the watch back on
• as the watch was powering back on, I went into the watch app on the iPhone 15 and selected to pair a NEW watch. It automatically recognized my watch and began the pairing process--this took less than 10 minutes. Despite having gone through the reset, all of my apps and settings were retained once my watch finished pairing.

Success!