I don't have a smartwatch anymore so I can't speak to the issue you're having. I do plan on getting the Google watch at some point, but not able to shell out that money right now. Getting the phone for basically free was still too much for me right now lol. I did have a Fitbit I liked for a while, but had a lot of issues with it.
As far as the screen protector, the glass one you showed me looked like it has a cutout for the fingerprint sensor, does yours have that? If so I don't think I would like that. I'll keep the TPU or whatever it is, one on for now, but probably gonna get the Whitestone Dome glass one here soon. Had that one on a previous phone a while back and really liked it.