Legacy app for Wear 1.0 needs to have different identification for Play Store so it doesn't get updated

I'm Wear 1 user (original LG G Watch). Latest update from Google Play Store removed support for Wear 1, found out by my watch face just disappearing and having to look for the issue.
So, I uninstalled the app and reinstalled the so called "legacy" app with the apk listed in the new version description.
Problem is that the app is still recognized by Google Play Store as to be updated. I have turned off auto-update for now but there is no way that I can't accidentally tap the manual update button when updating all my other apps.
Therefore the legacy app needs to be made somehow independent.
Or maybe you could still update the main app but have an additional side app providing Wear 1 support