Hi ranelson,
Thanks for reaching out here in the Apple Support Communities. We see that you would like to unpair your Apple Watch from your restored iPhone without erasing it, so that you don't lose data currently on the watch.
We're glad to help.
Unpairing will erase your Apple Watch, but it will also make a backup that you can then restore to a different Apple Watch.
Depending on what type of data you wish to keep, you will need either an iCloud backup or an encrypted backup using a computer.
This article has more details: Back up your Apple Watch
Take Care.