What is the best Apple Watch to pair with an iPhone 14 Plus?

Since Apple just announced a new model of Apple Watch today, the Apple Watch Series 10, that's what I'd opt for if I was buying a new Watch. But certainly anything in the last couple of generations would be fine. Even earlier models will probably work without major issues, though not all features may be available. I have a Series 6 watch and it's working just fine with my iPhone running the most recent version of iOS.

Regards.

Apple Watch Series 4 and later running watchOS 6 or later should work fine.