Apple Watch 3 Series won’t hold a charge

I read the thread about 3 series watches not holding a charge from 2019.

I’m having that same problem suddenly (won’t last 8 hours) and I’m running the following OS:

iPhone 7 OS: 15.0

Watch OS: 8.4.2

So frustrating. I’ve restarted, removed nearly all the apps I could from the phone. I thought it was dying bc I SOMETIMES use Spotify on my phone to stream to a Sonos speaker, but even the days I do not do that, days I barely access the watch except to check the time, it’s still runs down in under 8 hours. Help please.