Another vote for the Garmin Instinct 2: I use a Garmin Instinct 2 Solar, never ever connected it with Garmin Connect, I exclusively use it with GadgetBridge, and it supports all the things the watch does, including sleep tracking.
Might be relevant, the watch can do sleep tracking perfectly fine without any app, just by itself. When paired with GadgetBridge, you can see the graphs on your phone/tablet.
I have never used Garmin Pay, as my banks do not support it (and even if they did - I don't want to use Garmin Connect).