Can't erase old apple watch

I had an old Apple Watch 6 that I just replaced with a 10. I didn't realize the old watch was off when I unpaired it from my phone. Because of this, the watch is unpaired but still has all my stuff on it. I have tried to on the watch go to general > settings > reset and then click on "reset home screen layout". I get a new screen that tells me the watch will be erased but when I click "reset home screen" it only takes me back one screen. It doesn't reset the watch. As the watch is also still set up I can seem to be able to repair it to a phone to start from scratch.

I need to be able to erase it to trade it in.

Help....