How to in pair watch from a previous Apple ID and phone that I don’t have anymore

Sure. Visit appleid.apple.com. Log in to the old Apple ID using its email address and password. Go to devices and order the Apple ID to erase and forget the Apple Watch. Pair the watch with your new phone. Good luck.

You can ask apple to remove the activation lock online on this page;

Remove the Activation Lock Here.

Or this;

If you can't remember/gain access to the apple id that paired the watch to the phone.Take the watch and it's receipt with the serial number along with some photo id and any other proof of ownership to an Apple Store and request that they remove the Activation Lock for you.