Is that solution still working today 17/06/21? It didn't remain working for my Galaxy Watch.
I've found that simply switching the watch off and leaving it off for about an hour (or all night), always fixes Alti-Barometer completely. But, and it's a big BUT, the fix doesn't last for very long and gradually, over an hour or two, the 'Last 6 hours' charts will disappear and eventually so will the altitude and pressure readings. It seems as if the watch is each time gradually overloading its own 'brain' with Alti-Barometer app data? Samsung should sort this easily & quickly, especially as it's all, just fine for a while, after a prolonged shut-down of the watch.
I'm wonder if uninstalling some non-essential apps might help?
