Late to the game, similar problem.
Tried to pair but wouldn't take.
iPhone 8 (13.6. 1) , Apple Watch Series 2 right out the box.
Downloaded 14 beta
Was able to pair.
Removed Beta Profile.
Checked for updates.
Watch OS 5.3.8 available.
Downloaded and working. I don't know if Ill update it just yet to 6.