One of the biggest reasons I upgraded from the 3 to the 4 was because the 3 had poor Bluetooth performance. It was intermittent and choppy and I noticed it had to do with how far it was away from my ear. When my arm was on the backswing, that's when it would get choppy. If I held the watch near my ear it was fine.
The 4 performed a lot better but I would loose 40% of my charge on a 1-hour walk. I complained about it on this forum. I installed the latest update yesterday, went on a walk, and now my sound quality is choppy ! However, I noticed battery power was improved. I'm pretty sure they sacrificed Bluetooth quality for battery performance.
I am fed up with messing around with Samsung products. Their phone has been top notch, but I find the accessories lacking. I paid top dollar for these watches and I feel like I have been had by a snake-oil salesman, TWICE! I don't want to mess with it or figure out what the cause could be, I JUST WANT THEM TO WORK!!!
40% for an hour seems high especially if only using GPS and no music. I typically walk/run for roughly 90 minutes and my Classic 4 for the 3 days I checked it was 39 - 43% for GPS and music. With no music running I was usually 26 - 33%. My go to earbuds are the Jaybird Vista's using Spotify downloaded playlist to the watch I have zero dropouts or choppy sound. Recently bought the Google Pixel A buds and really like the weight and style but absolutely terrible bluetooth. Constant cutouts playing music. Got so bad the other day I planned ahead and brought the Vista's with me when I exercised. But totally agree with you regarding the Bluetooth on the phone using battery.