I bought a Galaxy Watch 46mm (SM-R800), 5 months ago. After the last software update (less than a month after I started using), problems started. Sensors (step, pressure and heart rate) are not working properly. Sometimes they work, sometimes don't. Sometimes step and HR working but pressure sensor not. When the sensors start working I don't have a problem for days. After then, suddenly, they decide to stop working. Another issue is, when I activate flight mode and deactivate after a moment, the bluetooth connection was not started and I have to start it manually. Same problem also valid for WiFi... Therefore, as an electronics engineer I think, this is a software issue.
My phone (Galaxy A50) had a similar WiFi connection problem (it looks connection was established but there is no internet access). After a software update the problem was fixed (thanks a lot). I hope that Samsung find a solution with an update and all those sensor problems are fixed.
You may right, coopaloop. Actually, there are two big problems, as I saw. First, sensors like this rarely cause problems at all... Even cheapest products mostly don't have this issues. Unfortunately, a great company like Samsung, couldn't find any solution, internet forums full of complaints about this watches and Samsung still keeps silent. I think, this situation damages its brand value. Second, wearable tech is getting popular and as I seen, Samsung products slowly lost their popularity because of the silent attitude of Samsung against all those complaints. I use Samsung products nearly ten years and I have would trust them. But after then I will think twice.