But that's how YouTube works. A channel grows to the point companies get interested in using it to promote their products. It's all very transparent, and it's on us as viewers to take that into account.
When I watch any review video with a content arrangement, I keep that in mind and tend to mainly go on the visuals, adding a pinch of salt to the actual advice (not that it's worthless, but it's certainly compromised). It's still a valuable video, and I can always cross-check what's being said with videos which aren't sponsored, for a more well-rounded perspective.