Samsung's Activity Score/Sleep Score function opaquely.How they are defined the company never described; that would not be an issue if they hadn't completely re-tweaked the algorithm behind it mid journey. A trip to their relevant subreddit [and from personal anecdote as well since I own a Galaxy Watch 6] would show sleep scores suddenly stumbling into high 90s for most users. This discrepancy makes any long term data useless.

Also, Samsung really cheaps out on battery life. OnePlus has a dual OS system[an RTOS for when full Wear OS functionality isn't required] and hence it can drag as high as 4 days. This one can barely eke half that runtime. MobVoi similarly builts in two displays [including at FSTN display] so eke out battery life.

Qi charging is also it's Achilles' heel. Sure, it is more comfortable than say, the latest Pixel Watch. But to note two points: a] the latter still goes to 50% significantly faster under identical circumstances and b] wireless charging makes it heat a lot; so if the ambient room temperature is high, it will throttle down it way furthur.

I have seen even the older Galaxy Watch 4 model [which only had 5W charging speed] heat so much in tropical weather that it would sometimes refuse to charge. [All the models from GW 4 to 8 use the wireless puck based charging; so I had be heavily surprised if throttling is somehow not a factor].

The one saving grace is that Samsung has longer upgrade cycles[longer software support]. I think they give updates [not equivalent to OS upgrades] for 4 years.