The main thing to note here is the Envy x360 actually has quite a small battery for a 15.6-inch laptop, at just 55.7 Wh. Typically we see at least 70 Wh in machines of this size, if not up near the 100 Wh range, but around 56 Wh is more like what we see in 13-inch notebooks. This already puts the Envy x360 at a disadvantage up against its competitors.
It therefore shouldn’t come as much of a surprise that the battery life produced by this laptop isn’t fantastic. In fact it’s quite poor, and from reading other reviews it seems this is the case whether you purchase the Ryzen Mobile model or the Intel model. If the battery was more in line with the display size, something around 75 Wh for example, battery life would be acceptable and in line with most other decent-enough laptops I’ve reviewed. Again, while I don’t have an apples to apples comparison just yet, I suspect Ryzen Mobile is slightly behind Intel 8th-gen in the power efficiency stakes, though at the same time, Ryzen packs more compute power.