I would rather call it a successor to the lem 12 pro as both the design and specs seems to have more similarity to it. Both the lem 15 and lem 12 pro has a 900mah battery, while the lem 14 has 1100mah. And the lem 14 is IP68 while the lem 15 is only IP67 and the lem 12 pro haven't got an IP rating. Apart from the difference in waterproofing and battery size, the lem 12 pro and the lem 14 has the exact same specs, and it would then be natural to see them as different models of the same generation, and the lem 15 should then be seen, as I said , as the successor to the lem 12 pro, not the lem 14.

I wouldn't trust that it covers 98% of the AdobeRGB colour space. Chinese companies sometimes come with claims that aren't exactly true, for example, for the lem 14 they claimed that it had an 1600mah battery, while in reality it had 1100mah.

When it comes to the heart rate monitor, it might not be a good one but it is most definitely a real one. Most likely it is the same PixArt PAH8001 as most of the other android watches uses.

The lem15 might not be priced as cheap as earlier generations of android watches, but if you compare it to for example Samsung Galaxy Watch 3, you'll see that with all you get in the lem 15 the price is still incredibly low.