How do you remove a Bluetooth device that was initially connected via the Bluetooth on an Apple Watch? There is no option for me to remove said device from Bluetooth, so I reconnect again later.

Unpair your Bluetooth accessory

1. Tap Settings > Bluetooth on your Apple Watch.
2. Tap  next to your accessory.
3. Tap Forget Device.

You are saying that a device configured in Bluetooth on your Apple Watch does not appear in Bluetooth in Settings on the Watch? What are you trying to disconnect? I can see both pairs of my AirPods on my Watch, and neither are connected. If I tap on the (i) next to a set, I see the option to forget the device.