How to restore Apple Watch fitness/health data after re-pairing with a new iPhone?

I bought a new iPhone and transferred my data from my old one, including my Apple Watch. The watch wasn't working properly. I unpaired it and re-paired it. As a result, a bunch of my workouts didn't transfer to the watch, my Activity Rings are completely different, and my limited-time rewards didn't transfer either. What should I do and how can I fix this? So, everything is on the iPhone, but not on the watch.